以下是引用stella131在2004-5-16 23:38:00的发言:帅哥~牛牛~~
3)~A -> ~B (否命题型加强)这个不懂~帅哥帮忙解释一下,可以吗? 
哈哈,是睡熊帅哥牛牛,我是鹦鹉学舌!!
6. The population of peregrine隼 falcons猎鹰 declined rapidly during the 1950's and 1960's and reached an all-time low in the early 1970's. The decline was attributed by scientists to the widespread use of the pesticide DDT in rural areas.
Which of the following, if true, gives the strongest support to the scientits claim?
(A) DDT was not generally in use in areas devoted to heavy industry. 无关
(B) In the time since the use of DDT was banned in 1972, the population of peregrine falcons has been steadily increasing.
(C) Peregrine falcons, like other birds of prey, abandon eggs that have fallen out of the nest, even if the eggs remain intact. 无关
(D) Starlings八哥, house sparrows, and blue jay-birds松鸦 the peregrine falcon prey on-were not adversely affected by DDT in their habitats.
(E) Other birds of prey, such as the osprey鱼鹰, the bald eagle, and the brown pelican鹈鹕, are found in the same areas as is the peregrine falcon. 无关
B“无DDT,隼增加”加强“有DDT,隼减少”!(哈哈,记得有DDT这道题,到FF的WORD讲义里,编辑->查找->DDT,立刻这道题就出来了)
[此贴子已经被作者于2004-5-17 0:16:36编辑过] |