1.?______ their economic system is reformed, the destiny of that country will be hard to predict.

A. Only after

B. Unless?

C. Now that

D. As long as

B【句意】除非改革自身的經(jīng)濟(jì)體制，否則那個(gè)國(guó)家的命運(yùn)將很難預(yù)測(cè)。

【解析】連詞和詞組詞義辨析。only after“只有在……以后”；unless“除非”；now that“既然，由于”；as long as“只要”。由句中關(guān)鍵詞“will be hard to predict將很難預(yù)測(cè)”及空格前后句的句意知“除非”符合語(yǔ)境，故B項(xiàng)正確。

2.?The scientists have made an _________ study of the viruses that cause the disease.

A. Exhausted?

B. Exhausting?

C. Exhaustive?

D. exhaustion

C【句意】科學(xué)家們對(duì)引起這種疾病的病毒進(jìn)行了詳盡的研究。

【解析】形容詞和名詞詞義辨析。exhausted“筋疲力盡的；耗盡的”；exhausting“使人疲憊不堪的”；exhaustive“詳盡的；徹底的；全面的”；exhaustion“筋疲力盡；耗盡”。由句中關(guān)鍵詞“study研究”和詞義辨析知“詳盡的”的符合語(yǔ)境，故C項(xiàng)正確。

3.?Amy was elected chairman of the committee by a ________ vote.

A. ambiguous?

B. synonymous?

C. Simultaneous?

D. unanimous

D【句意】經(jīng)過(guò)一致表決，艾米被選為委員會(huì)主席。

【解析】形容詞詞義辨析。ambiguous“模棱兩可的；含混不清的；不明確的”；synonymous“同義的；等同于……的”；simultaneous“同時(shí)發(fā)生（或進(jìn)行）的；同步的”；unanimous“（決定或意見）一致的，一致同意的”。由句中關(guān)鍵詞“vote表決”可知“（決定或意見）一致的”符合語(yǔ)境，故D項(xiàng)正確。