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问题 填空题

A．这是我的习惯。
B．你一定要看看这本书。太有意思了。
C．是啊，我喜欢多放糖。
D．好啊，但是我不太会跳。
E．不是，她是我的同事。

你好，我可以请你跳舞吗 ()

答案

参考答案：D

实验题

根据下列给出的实验装置图，回答：

（1）实验室常用无水醋酸钠和碱石灰混合加热制取甲烷，可选用的发生装置是             。 在做甲烷燃烧实验时，点燃前必须要             ，否则会发生危险。

（2）若用装置C制取CO2，并把CO2通入澄清石灰水中，较长时间一直未观察到石灰水变浑浊，其原因是生成的CO2中混有              气体。

（3）D是用CO还原CuO的实验装置图。实验时，① 中的现象是             ；② 中的现象是            。尾气应该            ，以防止和控制尾气中的             对空气的污染。

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单项选择题

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) of DDT 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 of DDT. 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) by DDT, and there were (17) insects which could act as natural (18) on these new "super-insects". Finally, it became clear that DDT 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.

9（）

A.wanted 

B.began 

C.decided 

D.arranged
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