【单选题】
It is clear that some chemicals can damage the health of animals and humans. (1) , this is not the only problem that (2) be caused by the careless use of chemicals.Chemicals can also (3) the ecological balance of the environment. If the ecological balance is disturbed, the results can be (4) serious.
The (5) ofDDT illustrates the problem.DDT, a chemical which kills insects, at first seemed to be a perfect answer (6) many problems. It would control insects that caused dangerous diseases, (7) insects that caused billions of dollars of damage to crops every year. Governments permitted and even (8) the use ofDDT. Farmers in many countries (9) to spray it on their crops. The (10) results were good:Damage to crops (11) down, and profits went up. However, the chemical had effects which the scientists didn’t see in (12) . First, it also killed insects which were the (13) enemies of the harmful insects and which were therefore beneficial to farmers. Second, and perhaps worse,DDT did not kill (14) harmful insect.A、few insects had natural resistance to the chemical. They (15) and reproduced in large numbers. In a few years there were large numbers of insects which were not (16) byDDT, and there were (17) insects which could act as natural (18) on these new "super-insects". Finally, it became clear thatDDT was not solving the insect problem. In fact, it was making the problem worse. It (19) became necessary to find a second (20) for the effects of the first.
A、as well asB、as well C、but D、also
正确答案
正在加载...
答案解析
正在加载...
根据网考网考试中心的答案统计，该试题：
66%的考友选择了A选项3%的考友选择了B选项26%的考友选择了C选项5%的考友选择了D选项
你可能感兴趣的试题
第1题：
A、ChArACtEristiC oFAmEriCAn CulturE thAt hAs BEComE Almost A trADition is to rEspECt thE sElF-mADE mAn—thE mAn who hAs risEn to thE top through his own EFForts, usuAlly BEginning By working with his hAnDs. WhilE thE lEADEr in BusinEss or inDustry or thE CollEgE proFEssor oCCupiEs A highEr soCiAl position AnD CommAnDs grEAtEr rEspECt in thE Community thAn thE Common lABorEr or EvEn thE skillED FACtory workEr, hE mAy tAkE pAins to point out thAt his FAthEr stArtED liFE inAmEriCA As A FArmEr o第2题：
A、ChArACtEristiC oFAmEriCAn CulturE thAt hAs BEComE Almost A trADition is to rEspECt thE sElF-mADE mAn—thE mAn who hAs risEn to thE top through his own EFForts, usuAlly BEginning By working with his hAnDs. WhilE thE lEADEr in BusinEss or inDustry or thE CollEgE proFEssor oCCupiEs A highEr soCiAl position AnD CommAnDs grEAtEr rEspECt in thE Community thAn thE Common lABorEr or EvEn thE skillED FACtory workEr, hE mAy tAkE pAins to point out thAt his FAthEr stArtED liFE inAmEriCA As A FArmEr o第3题：
In October 1961 atCrowley Field inCincinnati Ohio, an old deaf gentleman named WilliamE、Hoy stood up to throw the first ball of the World Series. Most people atCrowley Field on that day probably did not remember Hoy because he had retired from professional baseball 58 years earlier in 1903. However he had been an outstanding player and the deaf people still talk about him and his years in baseball.
WilliamE、Hoy was born in Houckstown Ohio on May 23, 1862. He became deaf when he was two year第4题：
Believe it or not, optical illusion can cut highway crashes.
Japan is a case in point. It has reduced automobile crashes on some roads by nearly 75 percent using a simple optical illusion.But stripes, called chevrons, painted on the roads make drivers think that they are driving faster than they really are, and thus drivers slow down.
Now theAmericanAutomobileAssociation Foundation for Traffic Safety in WashingtonD、C、is planning to repeat Japan’s success. Starting next year, the founda
当前位置：网考网 >> 教师资格证考试 >> 试题查看
