點揭模式：空白處點一下就顯示該格答案，再點可藏起。適合投影提問。Click mode: tap a blank to reveal that answer; tap again to hide it. Useful when projecting questions.
畫筆已開：可在筆記任何位置書寫。關閉畫筆後才可捲動、放大、點揭或開連結。筆跡會跟住文字，放大縮小都不會走位。寫完請按「分享」，在 iPad 選郵件寄出。Pen is on: write anywhere on the notes. Turn the pen off to scroll, pinch-zoom, tap blanks, or open links. Ink stays glued to the text when you zoom. When finished, tap Share and choose Mail on iPad.
HTMS 經濟科課堂筆記 | 編輯：Mr. Sam Wong | 重要聲明：本課堂筆記僅供已購買課本之學生使用，並僅限內部參考。HTMS Economics Lesson Notes | Editor: Mr. Sam Wong
Important: These lesson notes are intended only for students who have purchased the textbook and are for internal use only.
對齊課堂筆記 510／第 10 章（10.1–10.3、10.5）。貨幣與銀行、存款創造、貨幣需求與貨幣市場均衡見 507–509；國際貿易與匯率見 511–513。 Aligned with class notes 510 / Chapter 10 (sections 10.1–10.5). Money and banking, deposit creation, money demand and money-market equilibrium are in 507–509; trade and the exchange rate are in 511–513.
讀完本章，應能：
After this chapter you should be able to:
貨幣政策是指中央銀行透過控制貨幣供應（Ms）和／或名義及實質利率，以達到某些經濟目標的政策。
Monetary policy refers to the measures taken by the government or the central bank to achieve certain economic goals by adjusting money supply or interest rate.
這些目標包括穩定一般物價水平、刺激或減慢經濟增長、降低失業率等。課堂假設貨幣供應由中央銀行決定，貨幣供應曲線是垂直線：無論利率怎樣改變，貨幣供應量都維持不變。
Similar to fiscal policy, these goals include reducing the unemployment rate and cooling down an overheated economy. Money supply is set by the monetary authority, so the Ms curve is vertical.
貨幣政策包括下列兩種：
Monetary policy is mainly divided into two types:
透過增加貨幣供應和／或調低利率，刺激經濟。
The policy to raise the money supply or lower interest rate.
它是擴張性的，因為短期可以提高總產出。
It is expansionary because it can raise aggregate output in the short run.
透過減少貨幣供應和／或調高利率，壓抑過熱經濟。
The policy to lower the money supply or raise interest rate.
它是緊縮性的，因為短期可以降低總產出。
It is contractionary because it can lower aggregate output in the short run.
當貨幣供應增加，名義利率會下降。
When there is an increase in money supply, the nominal interest rate will decrease.
擴張：垂直 Ms 右移（Ms₀→Ms₁），沿向下斜的 Md，均衡由 E₀ 到 E₁：名義利率下降（i₀→i₁），貨幣量上升（M₀→M₁）。
Expansion: the vertical Ms shifts right (Ms₀→Ms₁). Along downward-sloping Md, equilibrium moves from E₀ to E₁: the nominal interest rate falls (i₀→i₁) and the quantity of money rises (M₀→M₁).
名義利率下降令外資流走，對本地貨幣需求減少，本地貨幣價值下跌（貶值），導致本地出口貨品價格（以外幣計算）下降，令出口淨值上升。
When the nominal interest rate decreases, foreign investment will flow out of the economy to earn a higher interest rate. The value of the domestic currency decreases, causing the price of domestic products relative to foreign products to decrease. This leads to an increase in net exports.
結果：貨幣供應增加會令總需求增加。
As a result, an increase in money supply will lead to an increase in aggregate demand.
擴張性貨幣政策令總需求增加，因此短期物價水平與總產出都會上升。
An expansionary monetary policy leads to an increase in aggregate demand. Therefore in the short run, the price level and aggregate output would increase.
擴張：AD 右移（AD₀→AD₁），沿向上斜的 SRAS，均衡由 E₀ 到 E₁：短期物價上升（P₀→P₁），產出升至 Y₁（可高於充分就業 Yf）。垂直 LRAS 停在 Yf。
Expansion: AD shifts right (AD₀→AD₁). Along upward-sloping SRAS, equilibrium moves from E₀ to E₁: the price level rises (P₀→P₁) and output rises to Y₁ (which can be above full-employment YF). Vertical LRAS stays at YF.
結論：它只能在短期令經濟擴張至超越充分就業水平（Yf）。垂直的長期總供應曲線意味着該經濟體系在長期必會停留於充分就業水平。
It can raise output above full employment only in the short run. A vertical long-run aggregate supply curve means the economy stays at the full-employment level in the long run.
當貨幣供應減少，名義利率會上升。借貸成本上升 → C、I ↓；外資流入 → 本幣升值 → (X−M) ↓。結果總需求減少（AD 左移）。短期物價水平與總產出都會下降。
When there is a decrease in money supply, the nominal interest rate will increase. The cost of borrowing increases → C and I fall. Foreign investment flows in, the domestic currency rises, and net exports fall. Aggregate demand decreases. In the short run, the price level and aggregate output would decrease.
緊縮：垂直 Ms 左移（Ms₀→Ms₁），沿向下斜的 Md，均衡由 E₀ 到 E₁：名義利率上升（i₀→i₁），貨幣量下降（M₀→M₁）。
Contraction: the vertical Ms shifts left (Ms₀→Ms₁). Along downward-sloping Md, equilibrium moves from E₀ to E₁: the nominal interest rate rises (i₀→i₁) and the quantity of money falls (M₀→M₁).
緊縮：AD 左移（AD₀→AD₁），沿向上斜的 SRAS，均衡由 E₀ 到 E₁：短期物價下降（P₀→P₁），產出降至 Y₁（可低於充分就業 Yf）。垂直 LRAS 停在 Yf。
Contraction: AD shifts left (AD₀→AD₁). Along upward-sloping SRAS, equilibrium moves from E₀ to E₁: the price level falls (P₀→P₁) and output falls to Y₁ (which can be below full-employment YF). Vertical LRAS stays at YF.
| 擴張性貨幣政策Expansionary monetary policy | 緊縮性貨幣政策Contractionary monetary policy | |
|---|---|---|
| 貨幣供應Money supply | ↑ | ↓ |
| 名義利率Nominal interest rate | ↓ | ↑ |
| 總需求Aggregate demand | ↑ | ↓ |
| 短期物價水平Short-run price level | ↑ | ↓ |
| 短期總產出Short-run aggregate output | ↑ | ↓ |
貨幣政策：公開市場操作、貼現率、法定儲備比率、印鈔。
Monetary policy: open-market operations, the discount rate, the required reserve ratio and printing money.
財政政策：加稅、轉移支付、基建、部委津貼。
Fiscal policy: a tax rise, a transfer, infrastructure spending or a ministry cash handout.
樂澄在屯門請茶兼職。若中央銀行增加貨幣供應、名義利率下降，店主借錢開分店的成本下降，消費與投資都會增加，總需求上升。短期店裏加班多了（產出升），珍珠和杯蓋也貴了（物價升）。這是課堂故事，不是把財政部發消費券當成貨幣政策。
Chloe works part-time at Try Tea in Tuen Mun. If the central bank raises money supply and the nominal interest rate falls, the owner’s cost of borrowing to open a branch falls, so consumption and investment rise and AD rises. In the short run she works more overtime (output up) and tapioca costs more (prices up). A government consumption voucher is fiscal, not monetary.
小練習 10.1AQuick check 10.1A
題 1Q1
文諾聽新聞說「教育局向學生發津貼」。這是貨幣政策嗎？
Marcus hears that “the Education Bureau will give students a cash subsidy.” Is this monetary policy?
答案：不是；屬財政政策（轉移／津貼）
Answer: No; it is fiscal (a transfer / subsidy)
貨幣政策：由中央銀行調 Ms 或利率。
Monetary policy: the central bank changing Ms or the interest rate.
財政政策：部委發錢不是央行工具。
Fiscal policy: a bureau cash handout is not a central-bank tool.
題 2Q2
擴張性貨幣政策在短期令物價和產出怎樣變？
In the short run, how do the price level and aggregate output change under expansionary monetary policy?
答案：兩者都上升
Answer: both increase
中央銀行主要以下列工具來改變貨幣供應：公開市場操作、貼現率、法定儲備比率、印發鈔票。
The government (or central bank) can use various monetary tools to affect the money supply to bring about an expansionary or contractionary effect: open market operations, the discount rate, the required reserve ratio, and printing money.
公開市場操作指中央銀行在公開市場買賣政府債券（或其他政府證券）。
Open market operations refers to the central bank’s buying and selling of government bonds in the market.
| 向公眾買入債券Purchase of government bonds | 向公眾出售債券Selling of government bonds | |
|---|---|---|
| 貨幣供應Money supply | 中央銀行需向公眾付款，公眾持有的現金和銀行可貸出的現金儲備增加，Ms增加Money paid out circulates or is deposited; Ms increases | 公眾從銀行戶口提取存款，公眾持有的現金和銀行可貸出的現金儲備減少，Ms減少Money received by the central bank reduces circulation or deposits; Ms decreases |
| 名義利率Nominal interest rate | ↓ | ↑ |
| 總產出Aggregate output | 借貸成本 ↓ → C、I ↑ → AD ↑ → Y ↑（擴張）Lower borrowing cost raises C and I; AD and Y rise（expansionary） | 借貸成本 ↑ → C、I ↓ → AD ↓ → Y ↓（緊縮）Higher borrowing cost cuts C and I; AD and Y fall（contractionary） |
貼現率是中央銀行向其他銀行收取的貸款利率。
Discount rate refers to the interest rate that the central bank charges on its loans to commercial banks.
調高貼現率：商業銀行向中央銀行借貸的機會成本上升，它們貸出超額儲備的意慾下降，可創造存款減少及貨幣供應減少。
Raising the discount rate: banks borrow from the central bank at higher cost, borrow less and loan out less; through deposit contraction, money supply decreases.
調低貼現率：商業銀行向中央銀行借貸的機會成本下降，它們貸出超額儲備的意慾上升，可創造存款增加及貨幣供應增加。
Lowering the discount rate: commercial banks can borrow from the central bank at lower cost, borrow more and loan out more; through deposit creation, money supply increases.
正確：貼現率 ↑ → 向央行借貸成本 ↑ → 銀行少借儲備、少貸款 → 存款收縮 → Ms ↓。
Correct: a higher discount rate raises the cost of borrowing from the central bank, so banks borrow less reserves and lend less; deposit contraction cuts Ms.
易錯：跳過儲備／存款創造，直接寫「市場利率一定立刻上升」。
Trap: skipping reserves / deposit creation and jumping straight to “the market interest rate must rise at once”.
法定儲備比率是銀行須把存款中的最低比例以儲備形式持有。
Required reserve ratio is the minimum fraction of deposits that banks are required to keep as reserve.
調高法定儲備比率：可貸出的超額儲備減少、可創造存款減少及貨幣供應減少。
Raising the required reserve ratio: banks have less excess reserves, or they even call back loans; through deposit contraction, money supply decreases.
調低法定儲備比率：超額儲備增加、可創造存款增加及 Ms 增加。
Lowering the required reserve ratio: banks have more excess reserves to loan out; through deposit creation, money supply increases.
法定儲備比率：不改變貨幣基礎，只改最大銀行乘數。
Required reserve ratio: does not change the monetary base; it changes the bank multiplier.
易錯：一間商業銀行向另一間商業銀行購買政府債券，體系儲備不變，不會增加體系貨幣供應。
Trap: a commercial bank buying government bonds from another commercial bank does not raise system-wide money supply — system reserves are unchanged.
透過印發鈔票以增加貨幣供應。中央銀行可印發鈔票以買入政府債券，令流通貨幣與銀行存款增加，貨幣供應增加；名義利率下降；C、I ↑ → AD ↑ → 產出上升，屬擴張性。
The central bank may print money to buy government bonds so that currency in circulation and bank deposits increase. Money supply increases, the nominal interest rate decreases, C and I rise, AD and output rise: expansionary.
| 工具Tool | 操作Action | MsMs | 名義利率Nominal i | AD 與 YAD and Y | 擴張／緊縮Type | 貨幣基礎Monetary base |
|---|---|---|---|---|---|---|
| 債券Bonds | 買入Purchase | ↑ | ↓ | ↑ | 擴張Expansionary | ↑ |
| 出售Sell | ↓ | ↑ | ↓ | 緊縮Contractionary | ↓ | |
| 貨幣基礎：買入時央行把現金或儲備注入銀行體系；出售則抽走。 Monetary base: a purchase injects cash or reserves into the banking system; a sale drains them. | ||||||
| 貼現率Discount rate | 調高Raise | ↓ | ↑ | ↓ | 緊縮Contractionary | ↓ |
| 調低Lower | ↑ | ↓ | ↑ | 擴張Expansionary | ↑ | |
| 貨幣基礎：貼現率↓，銀行向央行多借儲備，MB↑；貼現率↑則少借，MB↓。 Monetary base: a lower discount rate means banks borrow more reserves from the central bank, so MB rises; a higher rate means they borrow less, so MB falls. | ||||||
| 法定儲備比率Required reserve ratio | 調高Raise | ↓ | ↑ | ↓ | 緊縮Contractionary | — |
| 調低Lower | ↑ | ↓ | ↑ | 擴張Expansionary | — | |
| 貨幣基礎：不改變公眾現金或體系儲備總量（表中「—」）；改的是乘數。 Monetary base: does not change currency in public or bank reserves (“—” in the table); it changes the multiplier. | ||||||
| 印發鈔票Printing money | 印發Issue notes | ↑ | ↓ | ↑ | 擴張Expansionary | ↑ |
| 貨幣基礎：印鈔增加流通現金，MB↑。 Monetary base: newly printed notes raise currency in circulation, so MB rises. | ||||||
小練習 10.2A 貨幣基礎與乘數Quick check 10.2A Monetary base and the multiplier
題 1Q1
以下的貨幣政策工具會令貨幣基礎（已發行的貨幣總額）和最大銀行乘數增加、減少還是維持不變？
For each tool, does the monetary base (the total amount of issued money) and the maximum bank multiplier increase, decrease, or stay unchanged?
（a）公開市場購買政府債券：MB 增加；乘數 維持不變
（b）降低貼現率：MB 增加；乘數 維持不變
（c）降低法定儲備比率：MB 維持不變；乘數 增加
（d）印發鈔票：MB 增加；乘數 維持不變
Answer: (a) purchase bonds: MB up, multiplier unchanged; (b) lower discount rate: MB up, multiplier unchanged; (c) lower RR: MB unchanged, multiplier up; (d) print money: MB up, multiplier unchanged.
小練習 10.2BQuick check 10.2B
題 1Q1
提高貼現率會
A. 減少貨幣供應量，因為這會增加公眾手持的現金。
B. 減少貨幣供應量，因為這會減少商業銀行向中央銀行借取的儲備。
C. 增加貨幣供應量，因為這會增加商業銀行的創造貸款能力。
D. 增加貨幣供應量，因為這會減少商業銀行持有的儲備。
Raising the discount rate
A. reduces money supply because the public holds more cash.
B. reduces money supply because commercial banks borrow fewer reserves from the central bank.
C. raises money supply because banks’ lending capacity rises.
D. raises money supply because banks hold fewer reserves.
答案：B
Answer: B
正確：貼現率是向央行借貸的成本；升息令銀行少借儲備、少貸款，Ms 下降。
Correct: the discount rate is the cost of borrowing from the central bank. A rise means banks borrow fewer reserves and lend less, so Ms falls.
不是：因為公眾手持現金增加。
Not because: the public holds more cash.
題 2Q2
下列哪項可能會引致貨幣供應增加？
(1) 銀行借出她們的超額儲備。
(2) 法定儲備比率下降。
(3) 一間商業銀行向另一間商業銀行購買政府債券。
A. 只有 (1)、(2) B. 只有 (1)、(3) C. 只有 (2)、(3) D. (1)、(2) 及 (3)
Which of the following may raise money supply?
(1) Banks lend out their excess reserves.
(2) The required reserve ratio falls.
(3) One commercial bank buys government bonds from another commercial bank.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
答案：A
Answer: A
(3) 只是銀行之間轉債券，體系儲備不變，不能創造存款。
(3) is a transfer of bonds between banks; system reserves do not change, so deposits are not created.
結構題固定四步：指出合適政策 → 說明如何執行 → 貨幣市場效果 → 物價與產出效果（標 E1→E2、P1→P2、Y1→Y2／Yf）。
Structured questions use four steps: identify the suitable policy → how it is carried out → effects on the money market → effects on the price level and aggregate output (label E1→E2, P1→P2, Y1→Y2 / YF).
「擴張性」貨幣政策可紓緩失業問題。存在失業時，假設某經濟體系在短期面對失業問題，即均衡實質國民收入（Y₁）低於充分就業實質國民收入（Yf）（通縮缺口）。
Expansionary monetary policy can relieve unemployment. Unemployment is caused by an excess supply of workers: short-run equilibrium output Y₁ is below full-employment output YF (a deflationary gap).
1. 合適政策：採用擴張性貨幣政策。
1. Suitable policy: use expansionary monetary policy.
2. 如何執行：例如公開市場買入債券、調低貼現率、調低法定儲備比率或印發鈔票。
2. How it is carried out: e.g. buying government bonds, lowering the discount rate, lowering the required reserve ratio or printing money.
3. 貨幣市場：垂直 Ms 右移（Ms₁→Ms₂）。沿向下斜的 Md，均衡由 E₁ 到 E₂：名義利率下降（i₁→i₂），貨幣量上升（M₁→M₂）。借貸成本下降 → C、I ↑。
3. Money market: the vertical Ms shifts right (Ms₁→Ms₂). Along downward-sloping Md, equilibrium moves from E₁ to E₂: the nominal interest rate falls (i₁→i₂) and the quantity of money rises (M₁→M₂). Lower borrowing costs raise C and I.
失業／擴張：垂直 Ms 右移（Ms₁→Ms₂），沿 Md，均衡 E₁→E₂：i₁→i₂ 下降，M₁→M₂ 上升。
Unemployment / expansion: vertical Ms shifts right (Ms₁→Ms₂). Along Md, E₁→E₂: i₁→i₂ falls and M₁→M₂ rises.
4. 物價與產出：AD 由 AD₁ 右移至 AD₂；均衡 E₁→E₂；物價 P₁→P₂ 上升；產出 Y₁→Y₂（＝Yf），失業下降。當產出水平回復至充分就業水平時，市場在長期便不會有進一步的調整。
4. Price level and output: AD shifts from AD₁ to AD₂; equilibrium E₁→E₂; P₁→P₂ rises; Y₁→Y₂ (YF), reducing unemployment. When output returns to the full-employment level, there is no further market adjustment in the long run.
通縮缺口：AD 右移（AD₁→AD₂），沿 SRAS，E₁→E₂：P₁→P₂ 上升，產出由 Y₁ 升至 Y₂（＝Yf）。垂直 LRAS 停在 Yf。
Deflationary gap: AD shifts right (AD₁→AD₂). Along SRAS, E₁→E₂: P₁→P₂ rises and output rises from Y₁ to Y₂ (YF). Vertical LRAS stays at YF.
「緊縮性」貨幣政策可紓緩經濟過熱問題。經濟過熱時，假設某經濟體系在短期面對經濟過熱的問題，即 Y₁ 大於 Yf（通脹缺口）。
Contractionary monetary policy can relieve overheating. Overheating occurs when production capacity cannot keep pace with growing demand: short-run equilibrium output Y₁ is above full-employment output YF (an inflationary gap).
1. 合適政策：採用緊縮性貨幣政策。
1. Suitable policy: use contractionary monetary policy.
2. 如何執行：例如公開市場出售債券、調高貼現率或調高法定儲備比率。
2. How it is carried out: e.g. selling bonds, raising the discount rate or raising the required reserve ratio.
3. 貨幣市場：垂直 Ms 左移（Ms₁→Ms₂）。沿向下斜的 Md，均衡由 E₁ 到 E₂：名義利率上升（i₁→i₂），貨幣量下降（M₁→M₂）。借貸成本上升 → C、I ↓。
3. Money market: the vertical Ms shifts left (Ms₁→Ms₂). Along downward-sloping Md, equilibrium moves from E₁ to E₂: the nominal interest rate rises (i₁→i₂) and the quantity of money falls (M₁→M₂). Higher borrowing costs cut C and I.
過熱／緊縮：垂直 Ms 左移（Ms₁→Ms₂），沿 Md，均衡 E₁→E₂：i₁→i₂ 上升，M₁→M₂ 下降。
Overheating / contraction: vertical Ms shifts left (Ms₁→Ms₂). Along Md, E₁→E₂: i₁→i₂ rises and M₁→M₂ falls.
4. 物價與產出：AD 由 AD₁ 左移至 AD₂；均衡 E₁→E₂；物價 P₁→P₂ 下降；產出 Y₁→Y₂（＝Yf）。當產出水平回復至充分就業水平時，市場在長期便不會有進一步的調整。
4. Price level and output: AD shifts from AD₁ to AD₂; equilibrium E₁→E₂; P₁→P₂ falls; Y₁→Y₂ (YF). When output returns to the full-employment level, there is no further market adjustment in the long run.
通脹缺口：AD 左移（AD₁→AD₂），沿 SRAS，E₁→E₂：P₁→P₂ 下降，產出由 Y₁ 降至 Y₂（＝Yf）。垂直 LRAS 停在 Yf。
Inflationary gap: AD shifts left (AD₁→AD₂). Along SRAS, E₁→E₂: P₁→P₂ falls and output falls from Y₁ to Y₂ (YF). Vertical LRAS stays at YF.
正確：垂直 LRAS 停在充分就業（潛在產出）；AD 右移只推高物價。
Correct: a vertical LRAS stays at potential output; a rightward AD shift only raises the price level.
易錯：畫一條向上斜的 LRAS，或寫「長期產出繼續上升」。
Trap: an upward-sloping LRAS, or writing that output keeps rising in the long run.
Bob 發現學校飯堂和補習社都在加價，工廠加班，Y 已高於 Yf。這是通脹缺口：應用緊縮性貨幣政策（例如賣債或提高貼現率），而不是再印鈔刺激。
Bob finds the school canteen and his tutorial centre both raising prices, and factories on overtime, so Y is already above YF. That is an inflationary gap: use contractionary monetary policy (sell bonds or raise the discount rate), not more money-printing.
小練習 10.3AQuick check 10.3A
題 1Q1
假設經濟體系面對經濟過熱或通脹差距（Ye > Yf）。中央銀行能怎樣透過調整貨幣供應以解決問題？
If the economy faces overheating / an inflationary gap (Ye > Yf), how can the central bank adjust money supply?
答案：用緊縮性貨幣政策（減少貨幣供應）來解決經濟過熱。當貨幣供應減少時，名義利率上升；在其他因素不變下，實質利率（r = n − ie）也會上升。實質利率上升會導致私人消費開支和投資總額減少。總需求曲線向左移；總產出和就業水平下降。當產出水平回復至充分就業（Ye = Yf），經濟過熱問題便得以解決。
Answer: contractionary policy (reduce Ms) to cool overheating. When money supply falls, the nominal interest rate rises; other things equal, the real interest rate (r = n − ie) also rises. A higher real interest rate cuts private consumption and investment. AD shifts left; output and employment fall. Once output returns to full employment (Ye = YF), overheating is resolved.
小練習 10.3BPractice 10.3.1
題 1Q1
下列哪項有助消除通脹缺口？
(1) 中央銀行提高貼現率。
(2) 政府提高利得稅率。
(3) 中央銀行降低法定儲備比率。
A. 只有 (1)、(2) B. 只有 (1)、(3) C. 只有 (2)、(3) D. (1)、(2) 及 (3)
Which of the following help to eliminate an inflationary gap?
(1) The central bank raises the discount rate.
(2) The government raises the profits tax rate.
(3) The central bank reduces the legal reserve ratio.
A. (1) and (2) only B. (1) and (3) only C. (2) and (3) only D. (1), (2) and (3)
答案：A
Answer: A
(1) 緊縮貨幣；(2) 緊縮財政；(3) 降低法定儲備是擴張，會加大缺口。
(1) is contractionary monetary policy; (2) is contractionary fiscal policy; (3) is expansionary and widens the gap.
小練習 10.3C 長期實質產出Practice 10.3.1 Q2 Real GDP in the long run
試以總供應—總需求圖輔助，解釋為何擴張性貨幣政策在長期不能影響實質 GDP。
With the aid of an AS–AD diagram, explain why an expansionary monetary policy cannot affect real GDP in the long run.
先寫利率與 C、I，再寫 AD 右移；長期鎖定在潛在產出，只加價。圖必須有垂直 LRAS。
Write the interest-rate channel to C and I first, then the AD shift. Lock long-run output at potential output; only the price level rises. The diagram must have a vertical LRAS.
答案要點
Answer
擴張性貨幣政策會降低利率（1）
消費和投資會增加（1）
總需求增加（總需求曲線右移）（1）
然而長期總產出停留在潛在產出（1）
總需求增加只會導致物價水平上升（1）
Expansionary monetary policy will lower the interest rate. (1)
Consumption and investment will increase. (1)
Aggregate demand increases (AD curve shifts to the right). (1)
Yet aggregate output will stay at potential output in the long run. (1)
The increase in aggregate demand will only lead to an increase in the price level. (1)
正確圖
Correct diagram
垂直的長期總供應曲線停在潛在產出（1）
總需求曲線右移（1）
總產出維持不變（1）
A vertical long-run aggregate supply curve which stays at potential output. (1)
Aggregate demand curve shifts to the right. (1)
Aggregate output remains unchanged. (1)
小練習 10.3DQuick check 10.3D
題 1Q1
假設原初該經濟在高於充分就業的 E0 運作，這出現了 _________ 而 _________ 可幫助這經濟回復至長期均衡。
A. 通脹（產出）差距 …… 增加對貧窮人士的轉移支付
B. 通脹（產出）差距 …… 增加貼現率
C. 通縮（產出）差距 …… 增加對貧窮人士的轉移支付
D. 通縮（產出）差距 …… 增加貼現率
If the economy starts at E0 above full employment, this is a _________ and _________ can help it return to long-run equilibrium.
A. inflationary (output) gap …… increase transfers to the poor
B. inflationary (output) gap …… raise the discount rate
C. deflationary (output) gap …… increase transfers to the poor
D. deflationary (output) gap …… raise the discount rate
答案：B
Answer: B
題 2Q2
下列哪項能抵銷入息稅稅率下降對總需求的影響？
A. 資產貨幣需求下降 B. 進口意欲下降 C. 投資意欲上升 D. 法定儲備比率上升
Which of the following can offset the effect of a fall in the income-tax rate on aggregate demand?
A. Asset demand for money falls B. Desire to import falls C. Desire to invest rises D. The required reserve ratio rises
答案：D
Answer: D
減入息稅：擴張財政。
A cut in income tax: expansionary fiscal policy.
調高法定儲備：緊縮貨幣，可抵銷 AD 升幅。
Raising RR: contractionary monetary policy and can offset the rise in AD.
在香港，香港金融管理局（金管局，HKMA）負責推行貨幣政策。不過，由於聯繫匯率制度，香港的貨幣政策空間有限：香港利率深受美國利率影響，政府難以獨立改變貨幣供應或利率。
In Hong Kong, the Hong Kong Monetary Authority (HKMA) is responsible for implementing monetary policy. However, the scope of monetary policy is limited due to the linked exchange rate system. Interest rates of Hong Kong are heavily influenced by interest rates of the United States, and it is difficult for the government to affect money supply or the interest rate independently.
| 工具Tool | 香港情況Hong Kong |
|---|---|
| 公開市場操作Open market operations | 金管局可買賣外匯基金票據及債券；發行量少，對 Ms 影響有限。HKMA can buy and sell Exchange Fund Bills and Notes; few bonds are issued, so the influence on money supply is limited. |
| 貼現率Discount rate | 金管局向持牌銀行提供隔夜貸款；貼現率按美國聯邦基金目標利率及香港銀行同業拆息（HIBOR）計算，金管局影響力有限。HKMA offers overnight loans to licensed banks. The discount rate is calculated based on the US Federal Funds Target Rate and HIBOR; HKMA has limited influence. |
| 儲備／流動性要求Reserve / liquidity requirement | 香港銀行受流動性要求約束，效果類似法定儲備比率，但甚少用作貨幣工具。Instead of a required reserve ratio, banks are subject to a liquidity requirement, which affects money supply similarly, but it is rarely used as a monetary tool. |
家明以為金管局可以像其他央行那樣大幅減息救失業。聯繫匯率下，港元利率要跟美元走，獨立減息空間很小。不要把「香港沒有貨幣政策工具」寫成答案——有工具，但空間有限。
Ka Ming thinks HKMA can cut rates sharply to fight unemployment like other central banks. Under the link, Hong Kong rates follow the US dollar, so independent cuts are limited. Do not write “Hong Kong has no monetary tools” — the tools exist, but the room to use them is small.
小練習 10.4Quick check 10.4
題 1Q1
為甚麼香港難以獨立運用貨幣政策穩定產出？
Why is it difficult for Hong Kong to use monetary policy independently to stabilise output?
答案：聯繫匯率下利率受美國利率影響
Answer: under the linked exchange rate, HK interest rates are influenced by US rates
貨幣數量論主要探討一個經濟體系內的『貨幣數量』對『一般物價水平』和『產出』的影響。貨幣數量是指名義貨幣供應；建基於交易方程式這概念。（N.B. 假設貨幣流速是一常數，即不變。）
Inflation and the quantity theory of money: velocity of circulation of money is assumed to be constant. The QTM proposes a positive relationship between nominal money supply and the long-run price level. It is built on the equation of exchange.
最終產品的總開支 ≡ 最終產品的總值，即 MV ≡ PY。P 是（相對）物價水平［以當期的本地生產總值平減物價指數除以基期的平減物價指數（= 100）］；Y 是實質本地生產總值（或實質國民收入）；M 是貨幣數量（或名義貨幣供應）；V 是貨幣流通速度。
The equation of exchange focuses on money as a medium of exchange. It describes the relationship between total expenditure of consumers and total receipt of producers: MV ≡ PY.
貨幣流通速度是指某段時間內，每一單位貨幣流通的速度，即反映每 $1 在某段期間內轉手的次數。V = PY / M，可視為名義本地生產總值佔貨幣數量的比率。
Velocity of circulation of money (V) is the average number of times a unit of money is used in a period of time to buy goods and services. It is equal to the ratio of nominal output (PY) to nominal money supply (M): V = PY / M.
交易方程式：是一條恒等式：在貨幣經濟體系中，用於購買最終產品的貨幣的總值或總支出（MV）必定等於所購買的終端產品的總值（PY）。
Equation of exchange: an identity. Total spending on final goods (MV) must equal the total value of those goods (PY).
貨幣數量論：不是恒等式，也不等於交易方程式。
Quantity theory of money: not an identity, and not the same as the equation of exchange.
可斷定：若 M 與 PY 以同一比率增長，V 不變。
You can conclude: if money supply grows at the same rate as nominal income, velocity is constant.
不能斷定：物價上升或實質產出不變——沒有分開 P 與 Y 的資料就不能這樣寫。
You cannot conclude: that the price level is rising or real output is constant — you cannot split P from Y with that information alone.
公開試題 HKALE 2002 卷二 A 題 19Public Exam HKALE 2002 Paper 2A Q19
根據交易方程式，若貨幣供應與名義收入以同一比率增長，我們可以斷定
A. 物價水平正在上升。
B. 實質產出不變。
C. 貨幣流通速度不變。
D. 以上皆是。
According to the equation of exchange, if money supply grows at the same rate as nominal income, we can conclude that
A. the price level is rising.
B. real output is constant.
C. the velocity of circulation of money is constant.
D. All of the above.
答案：C
Answer: C
公開試題 HKALE 2004 卷二 A 題 19Public Exam HKALE 2004 Paper 2A Q19
某經濟數據：年份 1，貨幣供應 $45 百萬、本地生產總值（當時價格）$400 百萬；年份 2，貨幣供應 $50 百萬、本地生產總值 $600 百萬。由年份 1 到年份 2，下列哪一項必然正確？
A. 實質本地生產總值上升。
B. 一般物價水平上升。
C. 貨幣的流通速度上升。
D. 貨幣需求曲線向右移。
Year 1: money supply $45 million, GDP at current prices $400 million. Year 2: money supply $50 million, GDP $600 million. From year 1 to year 2, which must be correct?
A. There was a rise in real GDP.
B. There was a rise in the general price level.
C. There was a rise in the velocity of circulation of money.
D. The demand for money curve has shifted to the right.
答案：C
Answer: C
V1 = 400/45 ≈ 8.89；V2 = 600/50 = 12。只能肯定 V 上升；P 與 Y 無法分開。
V1 = 400/45 ≈ 8.89; V2 = 600/50 = 12. Only velocity must have risen; P and Y cannot be split.
貨幣數量論是解釋通貨膨脹的理論，建基於 MV ≡ PY，並假設貨幣流通速度頗為穩定。
The Quantity Theory of Money (QTM) proposes a positive relationship between nominal money supply and the long-run price level. It is a theory which explains inflation.
貨幣流通速度由消費模式、交易技術與交易頻率等因素決定；這些因素甚少改變，故假設 V 不變。實質國民收入在短期可能會變動，但在長期則會維持於充分就業的水平。
Velocity is determined by consumption patterns, technology of transactions and transaction frequency. As these factors seldom change, velocity is assumed to be constant.
小練習 10.5A 是非Practice 10.5.2 True or false
1. 貨幣數量論與交易方程式相同。答案：F
2. 貨幣數量論是恒等式。答案：F
3. 貨幣數量論是解釋通脹的理論。答案：T
4. 貨幣數量論假設貨幣流通速度不變。答案：T
1. The QTM is identical to the equation of exchange. F
2. The QTM is an identity. F
3. The QTM is a theory which explains inflation. T
4. The QTM assumes that the velocity of circulation of money is constant. T
假設：貨幣數量論假設流通速度由支付制度、經濟結構和技術等因素決定，基本上不變。
Assumption: constant velocity is an assumption of the QTM.
不是推論：不要寫「貨幣數量論推斷貨幣流通速度不變」。
Not a prediction: do not write that the QTM predicts that velocity is constant.
由於 MV ≡ PY 是恒等式，左方轉變的百分率必定等於右方。假設 V 固定，名義貨幣供應的轉變必定為名義國民收入帶來同比例轉變。因此貨幣數量（M）與名義國民收入（PY）成正向關係：%ΔM = %ΔP + %ΔY（當 %ΔV = 0）。
Percentage change in the components: as the equation of exchange is an identity, the change on both sides should be the same. Since velocity is assumed constant, %ΔM = %ΔP + %ΔY. An increase in money supply also implies an equal percentage increase in nominal output (PY).
假設：貨幣供應完全由中央銀行決定；貨幣流通速度不變，即 %ΔV = 0。物價水平（P）和實質國民收入（Y）都是可變的，兩者的轉變方向都與名義貨幣供應的轉變方向相同。推論：%ΔM ≈ %ΔP + %ΔY；%ΔM = %Δ(PY)。當貨幣數量（M）改變，P 和 Y 會隨之改變，P 和 Y 改變的百分率之和大約等於 M 改變的百分率。
In the short run, both the price level and real output are variable. An increase (decrease) in money supply may lead to an increase (decrease) in the price level and/or real output.
再假設實質國民收入維持於充分就業水平，實質產出不變（%ΔY = 0）。推論：%ΔM = %ΔP。只有物價水平會與名義貨幣供應作同方向、同比例轉變；P 改變的百分率等於 M 改變的百分率。
In the long run, real output remains constant at the full-employment level, therefore an increase (decrease) in money supply leads to an equal percentage increase (decrease) in the price level.
V、Y 不變時，P 與 M 成正比：M 加倍，P 加倍。
With V and Y fixed, P is proportional to M: double M, double P.
%ΔV = 0 時，%ΔM 由 %ΔP 與 %ΔY 分攤；長期 %ΔY = 0，全部落到物價。
With %ΔV = 0, %ΔM is split between %ΔP and %ΔY. In the long run %ΔY = 0, so the whole change falls on prices.
經濟直觀：「太多貨幣追逐太少物品」——Ms 增加時人們把額外貨幣花在物品與服務上，需求上升；長期實質產出不變，需求上升推高價格。
Economic reasoning — “too much money chasing too few goods”: when money supply increases, people spend the extra money on goods and services. Demand rises. In the long run real output is constant, so the increase in demand drives up prices.
教具：交易方程式／數量論計算器Lab: equation of exchange / QTM calculator 教具：貨幣政策與數量學說模擬器（模式 C）Lab: monetary policy & QTM simulator (mode C)小練習 10.5B 貼現率與 QTMPractice 10.5.2 Discount rate and the QTM
假設中央銀行調低貼現率。試用貨幣數量論解釋此政策對一般物價水平和實質產出在短期和長期的影響。
Suppose the central bank of Economy A lowers the discount rate. Explain, by using the quantity theory of money, the effects on the general price level and real output in both the short run and the long run.
答案：
商業銀行向央行借貸成本下降，會借得更多並貸出更多，經存款創造令 Ms 增加。
短期 V 不變但 P 與 Y 都可變，Ms 增加可能令一般物價水平和／或實質產出上升。
長期 V 與 Y（充分就業）不變，Ms 增加只令一般物價水平上升。
Answer:
Banks can borrow from the central bank at lower cost, borrow more and loan out more; through deposit creation, money supply increases.
In the short run, since V is constant but both P and Y may change, an increase in money supply may lead to an increase in the general price level and/or real output.
In the long run, since both V and Y are constant at full employment, an increase in money supply would lead to an increase in the general price level only.
題 2Q2
若貨幣供應增加 8%，短期一般物價水平上升 2%，實質產出的百分變動是多少？長期實質產出與物價又如何？
If there is an 8% increase in money supply, what is the percentage change in real output if there is a 2% increase in the general price level in the short run? What happens in the long run?
答案：短期 %ΔY = 8% − 2% = 6%。長期實質產出不變；%ΔP = %ΔM = 8%。
Answer: short-run % change in real output = 8% − 2% = 6%. Long run: real output unchanged; % change in the price level = % change in money supply = 8%.
公開試題 HKALE 2006 卷二 A 題 11Public Exam HKALE 2006 Paper 2A Q11
貨幣數量論推斷
(1) 一般物價水平的轉變由實質貨幣存量的轉變決定。
(2) 名義國民收入的轉變與名義貨幣存量的轉變成正向關係。
(3) 經濟體系永遠處於充分就業水平。
A. 只有 (1) B. 只有 (2) C. 只有 (2)、(3) D. (1)、(2) 及 (3)
The quantity theory of money predicts that
(1) changes in the general price level are determined by changes in the real money stock.
(2) changes in the nominal national income are positively related to changes in the nominal money stock.
(3) the economy is always at the full-employment level.
A. (1) only B. (2) only C. (2) and (3) only D. (1), (2) and (3)
答案：B
Answer: B
(1) 不是：P 由名義貨幣存量決定，不是實質貨幣存量（M／P）。
(1) No: P is determined by the nominal money stock, not the real money stock (M／P).
(2) 是：V 不變時，M 與 PY（名義國民收入）成正向關係。
(2) Yes: with V constant, M and PY (nominal national income) are positively related.
(3) 不是：充分就業是古典 QTM 的假設，不是推斷。
(3) No: full employment is an assumption of the classical QTM, not a prediction.
公開試題 HKALE 2005 卷二 A 題 18Public Exam HKALE 2005 Paper 2A Q18
假設貨幣流通速度不變。根據交易方程式，若貨幣供應增長率小於實質本地生產總值增長率，我們可以斷定
A. 出現通縮。
B. 通脹率正在下降。
C. 失業率正在上升。
D. 實質 GNP 增長率高於通脹率。
Suppose the velocity of circulation of money is held constant. According to the equation of exchange, if the growth rate of money supply is smaller than that of real GNP, we can conclude that
A. there is deflation.
B. the inflation rate is falling.
C. the unemployment rate is rising.
D. the growth rate of real GNP is higher than the inflation rate.
答案：A
Answer: A
%ΔV = 0 時，%ΔP = %ΔM − %ΔY。若 %ΔM < %ΔY，則 %ΔP < 0，即通縮。
With %ΔV = 0, %ΔP = %ΔM − %ΔY. If money growth is smaller than real GNP growth, %ΔP is negative: deflation.
小練習 10.5CQuick check 10.5C
題 1Q1
某經濟的實質產出有所增長，其增長率較貨幣供應的增長率為低。根據貨幣數量論，我們可得出結論：
(1) 物價水平正上升。
(2) 失業率正下降。
(3) 貨幣流通速率正下降。
(4) 名義產出正上升。
A. 只有 (1)、(2) B. 只有 (1)、(4) C. 只有 (2)、(3) D. 只有 (3)、(4)
Real output grows, but more slowly than money supply. According to the QTM:
(1) The price level is rising.
(2) The unemployment rate is falling.
(3) Velocity is falling.
(4) Nominal output is rising.
A. (1) and (2) only B. (1) and (4) only C. (2) and (3) only D. (3) and (4) only
答案：B
Answer: B
可斷定：%ΔP = %ΔM − %ΔY > 0，物價上升；%Δ(PY) = %ΔM > 0，名義產出上升。
You can conclude: %ΔP = %ΔM − %ΔY > 0, so the price level rises; %Δ(PY) = %ΔM > 0, so nominal output rises.
不能斷定：失業率（不是 QTM 的必然結論）。V 是假設不變。
You cannot conclude: that unemployment is falling. V is assumed constant; unemployment is not a necessary QTM result.
題 2Q2
下列哪項有關古典貨幣數量論的陳述是不正確的？
A. 貨幣流通速度和實質產出均假設為不變。
B. 貨幣供應的任何改變會導致名義產出產生同等比例的改變。
C. 當貨幣供應不斷下降時，通縮便會出現。
D. 物價水平的任何改變會導致貨幣供應產生同等比例的改變。
Which statement about the classical quantity theory of money is incorrect?
A. Velocity and real output are both assumed constant.
B. Any change in money supply leads to an equiproportional change in nominal output.
C. When money supply keeps falling, deflation occurs.
D. Any change in the price level leads to an equiproportional change in money supply.
答案：D
Answer: D
正確：古典 QTM 是 Ms 決定 P。
Correct: classical QTM says money supply determines the price level.
不是：P 決定 Ms。
Not: the price level determining money supply.
貨幣中性是指在長期，貨幣數量的改變只會影響一般物價水平，而不會影響實質產出水平、實質工資等實質變數。
Money is neutral in the sense that a change in money supply will not affect real values. In the long run, the change in money supply cannot affect real output, but can only affect nominal values (through the price level).
1. 長期只有貨幣存量增長才會帶來通脹，因為 V 與總產出假設不變。
2. 例如貨幣數量增加 100%：一般物價水平上升 100%，實質產出維持不變。
1. Only an increase in money supply will bring inflation in the long run, as velocity and aggregate output are assumed constant.
2. This implies the neutrality of money in the long run.
通脹：一般物價水平持續上升。
Inflation: a sustained rise in the general price level.
一次性轉變：Ms 一次性增加、物價一次性上升，不是通脹。
A one-off change: a one-off rise in Ms (and a one-off rise in P) is not inflation.
嘉欣用手機計算機把名義 GDP 除以 M2。這只是 V。老師問物價升了多少，她不能只憑這兩個數字作答——還要 QTM 假設，或另外知道 P 或 Y。
Eslyn divides nominal GDP by M2 on her phone. That is only V. If asked how much prices rose, those two numbers are not enough — she needs QTM assumptions, or separate data on P or Y.
QTM 對長期 Ms 轉變的推斷與 AD–AS 模型一致。增加貨幣供應有擴張效果；當經濟在長期均衡，總需求增加造成通脹缺口，投入價格上升，短期總供應減少，直至充分就業產出恢復，長期結果是通脹。
The QTM’s long-run prediction is consistent with the AD–AS model. Increasing money supply has an expansionary effect. When the economy is in long-run equilibrium, an increase in aggregate demand results in an inflationary gap, which leads to an increase in input prices. Short-run aggregate supply decreases until the full-employment level of output is restored. This results in inflation in the long run.
小練習 10.5D 惡性通脹Quick check 10.5D Hyperinflation
津巴布韋在 2000 年代經歷惡性通脹。在同一期間，津巴布韋政府印發面值 100 萬億的鈔票，面值全球最大。試利用貨幣數量論解釋這個現象。
Zimbabwe experienced hyperinflation in the 2000s. In the same period the government printed notes with a face value of 100 trillion, the largest in the world. Explain using the QTM.
答案：根據貨幣數量論，在長期，V 和 Y 是常數。物價水平與貨幣供應會作同方向變動。無節制印鈔令貨幣供應大幅增加，物價水平急速上升，因而出現惡性通脹。
Answer: In the long run, V and Y are constant. The price level moves in the same direction as money supply. Unrestrained note-printing raised money supply sharply, so the price level rose rapidly: hyperinflation.