问题 选择题

研究物质的性质时.我们曾做过许多实验.下列有关实验现象的描述与实验事实不相符的是(  )

实验内容实验现象
A.红磷在氧气中燃烧有大量白烟生成
B.硝酸铵固体溶于水溶液温度显著降低
C.细铁丝在氧气中燃烧有红棕色固体生成
D.氢氧化铜跟稀硫酸完全反应有蓝色溶液生成

A..A

B..B

C..C

D..D

答案

A、红磷在氧气中燃烧,产生大量的白烟,放出大量的热,故选项说法正确.

B、硝酸铵溶于水中,吸收热量,使溶液温度降低,故选项说法正确.

C、细铁丝在氧气中剧烈燃烧,火星四射,放出大量的热,生成一种黑色固体,故选项说法错误.

D、氢氧化铜跟稀硫酸完全反应生成蓝色的硫酸铜溶液,故选项说法正确.

故选C.

解答题
阅读理解

阅读理解。

     Expressions about water are almost as common as water itself. But many of the expressions using water

have Unpleasant meanings.

     The expression "to be in hot water" is one of them. It is a very old expression. "Hot water" was used 500

years ago to mean being in trouble. One story says it got that meaning from the custom of throwing extremely

hot water down on enemies attacking a castle.

     That no longer happens. But we still get in "hot water". When we are in"hot water", we are in trouble. It

can be any kind of trouble-serious or not so serious. A person who breaks a law can be in hot water with the

police. A young boy can be in hot water with his mother, if he walks in the house with dirty shoes.

     Being in "deep water" is almost the same as being in hot water. When you are in deep water. you are in a

difficult position. Imagine fl person who cannot swim being thrown in water over his head.

     You are in deep water when you are facing a problem that you do not have the ability to solve. The problem

is too deep. You can be in deep water, for example, if you invest in stocks without knowing anything about the

stock market.

     "To keep your head above water" is a colorful expression that means staying out of debt. A company seeks

to keep its head above water during economic hard times. A man who loses his job tries to keep his head above

water until he finds a new job.

     "Water over the dam" is another expression about a past event. It is something that is finished. It cannot be

changed. The expression comes from the idea that water that has flowed over a dam cannot be brought back

again.

1. Which of the following two expressions have almost the same meaning? [ ]

A. To be in hot water; To be in deep water.

B. To be in hot water; To keep your head above water.

C. To be in deep water; Water over the dam!

D. Water over the dam; To be in hot water.

2. If a person tries t0 keep his head out of water,we can say that _____. [ ]

A. he is in danger of losing his life

B. he is trying to pay off his debt

C. he is trying to keep his promise

D. he is trying not to get into debt

3. What can you infer from the passage? [ ]

A. "To be in hot water" can only be used t0 mention serious trouble.

B. "Water over the dam" is an expression about a future event.

C. Water could be used in the war in the past.

D. All of the expressions using water have unpleasant meanings.

4. This passage is written mainly to tell us _____. [ ]

A. the use of water

B. how to use some expressions of water

C. expressions about water and their meanings

D. expressions with negative meaning