移架操作时要掌握八项操作要领，做到快、匀、够、正、直、稳、严、净（）

【3分】已知某溶液中存在较多的H⁺、、，则在该溶液中不能大量存在的离子组是(    )

①K⁺、、F^-  ②K⁺、Ba²⁺、Cl^-  ③Fe²⁺、Cl^-、Br^-  ④K⁺、Na⁺、ClO^-

A．①②③④

B．只有②③④

C．只有①③④

D．只有②③

简述集中操作和管理系统的功能和特点。

预应力钢绞线表面允许有轻微的浮锈，但不得锈蚀成肉眼可见的麻坑。

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 a 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. 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．

Another common expression, “to hold water”, is about the strength or weakness of an idea or opinion that you may be arguing about. It probably comes from a way of testing the condition of a container. If it can hold water, it is strong and has no holes in it. If your argument can hold water, it is strong and does not have any holes. If it does not hold water, then it is weak and not worth debating.

“Throwing cold water” also is an expression that deals with ideas or proposals. It means that one doesn’t like an idea. For example, you want to buy a new car because the old one has some problems. But your wife throws cold water on the idea because she says a new car costs too much.

This is our Special English program, WORDS AND THEIR STORIES. It was written by Marilyn Christiano. I’m Rich Kleinfeldt. See you next time.

小题1:According to the passage, expressions about water __________.

A．are very common

B．have unpleasant meanings

C．are very interesting

D．are easy to understand小题2:The expression “hot water” _________.

A．is not used nowadays

B．has a long history

C．means arguing with others

D．only means serious trouble小题3: Which of the following expressions have the similar meaning?

A．“Throwing cold water” and “deep water”

B．“Hot water” and “water over the dam”

C．“Deep water” and “water over the dam”

D．“Hot water” and “deep water”小题4: If you signed an agreement with Tom yesterday and want to change it now, Tom may say “_______”.

A．You should keep your head above water

B．You can’t throw cold water

C．It is water over the dam

D．Don’t be in deep water小题5: What would be the best title for the passage?

A．Water

B．Expressions about water

C．Several common expressions

D．Water and everyday English

2010年11月9日，中 * * 办公厅、国务院办公厅公布《关于加强和改进城市社区居民委员会建设工作的意见》，进一步完善城市居民自治制度，为未来10年城市社区居委会改革绘制了蓝图。对此认识正确的是（）。

①与农村村民委员会一样，城市社区居民委员会也是中国的基层群众自治组织。

②实行城市居民自治有利于保证人民群众依法直接行使民主权利。

③城市社区居委会作为基层国家机关主要职责是协助政府做好工作。

④基层群众自治制度与人民代表大会制度、中 * * 党领导的多党合作和政治协商制度、民族区域自治制度一起，列为中国社会主义民主政治的四大支柱之一。

⑤坚持和完善基层群众自治制度，是坚持中国特色社会主义政治发展道路的重要内容。

A.①②③④⑤

B.①③④⑤

C.②③④

D.①②④⑤