问题 选择题

在托盘天平两端的烧杯中加入同浓度同体积的足量盐酸,当向两个烧杯中分别加入0.1mol两种金属充分反应后,而在某一端要再放一个0.2克砝码,天平才能平衡,则这两种金属是(  ) 

A.Al和Fe

B. Mg和Al

C.Fe和Cu

D.Na和Mg

答案

答案:B

题目分析:两种金属的量相同,反应后有0.2g的质量差,所以这两种金属为Mg和Al。答案选B。

点评:本题属于初中的质量差习题,非常简单基础。

阅读理解

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Sometimes children do not do what their parents tell them to do. When this happens, a parent tries to help the child to do the right thing. When this does not work, the parent usually punishes the child.

There are many things that a parent can do. One thing that people have done is to spank (打屁股) the child. When a parent spanks a child, they will use their hand or a hard object to strike them on their bottom. This is meant to show the child that they have done something wrong.

One parent remembers being spanked when he was a child. His parents used a wooden spoon. When he spanked his own children with his hand, he saw that he put a red mark on his child’s leg. He never did that again.

One problem with spanking is that it teaches the child to hit someone when they do not like what the other person is doing. Another problem with spanking is that the parent is usually angry and can hit the child too hard. Sometimes parents will use spanking for everything and not try other ways to get the child to do the right thing.

Many parents are not sure of what to do instead of spanking. Some people think that their religion tells them that spanking is okay. Some think that the law lets them do it. The courts (法院) say that parents have the right to teach their children how to behave.

Other things should be tried before a parent decides to spank a child. Telling the child exactly what is wanted from them can be one thing. Giving a child more than one choice is another thing that can be tried. Getting down to the child’s level and taking a more child-friendly approach (方法) can help as well.

67. According to the passage, when children do something wrong, one thing that parents usually do to punish them is to ________.

A. strike them on the bottom

B. try to help them do the right thing

C. teach them what to do

D. take them to court

68. Which of the following is NOT the problem caused by spanking?

A. It teaches the child to hit others when they offend(使人不快) him or her.

B. The parent may get angry and hit the child too hard.

C. Sometimes parents may use spanking for everything.

D. It makes parents try other ways to make the child do right.

69. Which of the following can best describe the writer’s attitude towards spanking?

A. favorable (赞同的)   B. indifferent (不关心)

C. interested          D. unfavorable

70. From this passage, we can conclude that ________.

A. Good children always do the right thing.

B. Parents should try their best to avoid (避免) spanking their children.

C. Parents have no choice but to spank their children when they do something wrong.

D. Children can have more than one choice to avoid being spanked.

单项选择题