DDT, the most powerful pesticide the world had ever known,exposed nature’s vulnerability. Unlike most pesticides, which effect- __1__ tiveness is limited to destroy one or two types of insects, DDT is __2__ capable of killing hundreds of different kinds at once. Developed in 1939, it first distinguished itself during the World War II, cleaning __3__ South Pacific islands of malaria-caused insects for U.S. troops, while __4__in Europe being used as an effective de-lousing power. Its inventor was awarded by the Nobel Prize. __5__ When DDT became available for civilian use in 1945, there were only a few people who expressed the second thought about this __6__ new miracle compound. One was nature writer Edwin Way Teale,who warned, “A spray as discriminate as DDT can upset the economy __7__ of nature of all insects are good, but if they are killed, things __8__ go out of kilter right away.” Another was Rachel Carson, who wrote to the Reader’s Digest to propose an article about series of __9__ tests on DDT being conducted not far from which she lived in Maryland. __10__
答案：
1.which—whose。whose在这里作关系限定词，与effectiveness构成名次词组在关系分句里作主语。whose的主语可以是人，也可以是物。
2.destroy—destroying。be limited to 词组里的to并不是不定式标记to，而是介词to，要谨访介词to“冒充”不定式to。其他类似的词组还有be opposed to, object to, get used to等等。考试大
3.cleaning—clearing。clean和clear这对形近而且意近的动词容易被混淆，但是clean指“使某地方没有灰尘，使干净”，而clear强调“清理不需要的东西，而且clear 可与of连用，而clean很少。（这两个词的改错之前也有遇到过，大家都要记住啦！）
4.caused—causing。此句中malaria－causing insects 相当于insects that caused malaria，因此是主动关系，所以应选择-ing形式。
5.by－/。the Nobel Prize实际上是award的另一个宾语，还原成主动结构是…awarded the inventor the Nobel Prize.所以这里应删掉by。
6.the－/。短语second thought或second thoughts意为“仔细斟酌，三思”，如：Robert didn’t give a second thought to borrowing $2,000 from him.
7.discriminate－indiscriminate。discriminate有“区别”之意，indiscriminate意为“不加以选择，不分青红皂白”。从上下文来看DDT的特点是没有分辨性：它既能杀死有害的昆虫又能杀死有益的昆虫。
8.but－and/so。本句的两个意群的关系是顺接，不是转折，因此应选用顺接的连词，如and和so等。
9.^series－a。series这个名词属于单数复数同形，它经常与a和of构成词组a series of表示“一系列的”。
10.which－where。from这个介词后面应接一个介词表具体方位，因此这里只能用表方位的副词where。
