1. Suppose there were a flood or an earthquake and the people could not be reached by trains or trucks. _______ packages of food could be dropped from planes, the people might starve.

　　A. Until

　　B. Before

　　C. Unless

　　D. If only

　　2. Mary has long had the desire _______ a famous writer even though the study of writing would require years of sacrifice on her part.

　　A. for becoming

　　B. to become

　　C. of becoming

　　D. becoming

　　3. This is so difficult a problem that the scientist is known to _______ on it for about ten years, but hasn’t found a solution yet.

　　A.have worked

　　B. have been working

　　C.be working

　　D. work on

　　4. A majority _______ collectively may be regarded as a being whose opinions and, most frequently, whose interests are opposed to those of another being, which is styled a minority.

　　A. taking

　　B. takes

　　C. take

　　D. taken

　　5. I would have passed the college entrance examinations _______ I missed some of the questions and gave the wrong answers.

　　A. but

　　B. because

　　C. as

　　D. in that

　　【答案及解析】：

　　1. Cunless“除非”，從主從句的邏輯關(guān)系上看是惟一正確選擇。句意：“假如發(fā)生了水災(zāi)或地震，且火車、汽車又無(wú)法通至災(zāi)區(qū)，除非用飛機(jī)空投，否則那里的人們就會(huì)餓死�！�

　　2. Bto become在句中做desire的定語(yǔ)，意為“成為一個(gè)著名作家的愿望”，其他結(jié)構(gòu)一般不做desire的定語(yǔ)。

　　3. B不定式to have been working…做主語(yǔ)scientist的補(bǔ)足語(yǔ)，用完成進(jìn)行式表示：“這個(gè)科學(xué)家已對(duì)如此復(fù)雜的問(wèn)題研究了大約十年，并且還要繼續(xù)研究下去�！�

　　4. Dtaken在句中做后置定語(yǔ)，修飾majority, 由于與所修飾的詞是動(dòng)賓關(guān)系，所以應(yīng)用過(guò)去分詞，a majority which is taken collectively可以理解為“(把)大多數(shù)人作為一個(gè)整體”。

　　5. A句中but表示轉(zhuǎn)折，后面陳述的是事實(shí)情況：“……看錯(cuò)了問(wèn)題所以沒(méi)答對(duì)”。暗指“若不是看錯(cuò)了題，就會(huì)答對(duì)而且通過(guò)考試”。因此句子前半部分用的是虛擬語(yǔ)氣would have passed。