Deflation is an economic theory relating changes in the price levels to changes in the quantity of money. In its developed (1) , it constitutes an analysis of the (2) underlying inflation and deflation. As (3) by the English philosopher John Locke in the 17th century, the Scottish (4) David Hume in the 18th century, and (5) , it was a weapon (6) the mercantilists, who were thought to equate wealth with money. If the (7) of money by a nation merely raised (8) , argued the quantity theorists, then a "favourable" balance of trade, (9) desired by mercantilists, would increase the supply of money but would not in-crease (10) . In the 19th century the quantity theory (11) to the ascendancy of free trade over protectionism. In the 19th and 20th centuries it played a part in the (12) of business cycles and in the theory of foreign (13) rates.
The (14) theory came under attack during the 1930s, (15) monetary expansion seemed ineffective in combating deflation. Economists argued that the levels of investment and government spending were more important than the money supply in determining economic activity.
The tide of opinion (16) again in the 1960s, when experience (17) post-World WarⅡ inflation and new empirical (18) of money and prices— (19) A Monetary History of the United States (1963) by Milton Friedman and Anna Schwartz—restored much of the quantity theory’ s lost prestige. One implication of this theory is that the size of the stock of money must be considered when shaping governmental policies (20) to control prices and maintain full employment.
9（）
A.since
B.if
C.before
D.as
参考答案：D
解析：
[解题思路] 本题考核的知识点是：连词辨析。[A] 选项since，可以做介词，但后面必须跟名词；乜可以做连词表示“因为”，但后面必须跟主谓俱全的从句，因此可以排除。[B] 选项if引导条件从句，但整个句子开头已经有了“If”引导条件，不能逻辑上再次重复，因此叮以排除。[C]选项表示“在……之前”，要么做介词后面加名词，要么引导从句，后面接主谓成分，故可以排除。 [D]选项as除了引导原因状语和时间状语之外，经常用于“as expected/desired by sb”等结构，表示“正如……所料、所期待的那样”，满足本题的需要，故入选。
