DDT, the most powerful pesticide the world had ever known, exposed nature’s vulnerability. Unlike most pesticides, which effecti

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问题     DDT, the most powerful pesticide the world had ever known, exposed
nature’s vulnerability. Unlike most pesticides, which effectiveness is limited (1)______
to destroy one or two types of insects, DDT was capable of killing hun- (2)______
dreds of different kinds at once. Developed in 1939, it first distinguished
itself during World War II, cleaning South Pacific islands of malaria- (3)______
caused insects for U.S. troops, while in Europe being used as an effective (4)______
de-lousing powder. 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 thoughts about this new miracle (6)______
compound. One was nature writer Edwin Way Teale, who warned, "A spray
as discriminate as DDT can upset the economy of nature as much as a revo- (7)______
lution upsets social economy. Ninety percent of all insects are good, but if (8)______
they are killed, things go out of kilter right away." Another was Rachel Car
son, 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)______
The magazine rejected the idea.
(4)

选项

答案caused — causing

解析 动词的-ed分词和-ing分词作名词修饰语时,-ed分词表示的是动词和所修饰名词间的被动关系,而-ing形式表示的则是主动关系,此句中malaria-causing insects相当于in-sects that caused malaria,因此是主动关系,所以应选择一ing形式。详细说明请参照本书第37页关于动词的-ed分词和-ing分词区别的解释。
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