下列实验操作或对实验事实的叙述正确的有几个:() ①用氨水清洗做过银镜反应的试管

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问题:

下列实验操作或对实验事实的叙述正确的有几个:(    )

①用氨水清洗做过银镜反应的试管;

②配制一定物质的量浓度的溶液时,定容时仰视则溶液浓度偏低。

③用湿润的pH试纸测定稀盐酸的pH;

④用碱式滴定管量取20.00 mL 0.1mol/LKMnO4溶液

⑤将Na2CO3固体在瓷坩埚中加热熔融;

⑥不慎将苯酚溶液沾到皮肤上,立即用NaOH稀溶液清洗

⑦向沸腾的NaOH溶液中滴加FeCl3溶液,制备Fe(OH)3胶体

⑧配制FeSO4溶液时,需加入少量铁粉和稀硫酸

A.5

B.3

C.2

D.1

考点:化学实验的基本操作化学实验安全危险化学品的标志化学药品的变质
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典型失神发作的特征是()。

A.发作性短暂意识障碍

B.发作性多动

C.抽搐

D.发作性精神异常

E.发作性缄默不语

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When you leave, please turn off the light_____ energy.

A.save

B.saving

C.saved

D.to save

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道德的职能包括( )。

A.道德的调节职能

B.道德的教育职能

C.道德的认识职能

D.道德的行为职能

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Passage Two

If there is one thing I’m sure about, it is that in a hundred years from now we will still be reading newspapers. It is not that newspapers are a necessity. Even now some people get most of their news from television or radio. Many buy a paper only on Saturday or Sunday. But for most people reading a newspaper has become a habit passed down from generation to generation.

The nature of what is news may change. What basically makes news is what affects our lives—the big political stories, the coverage of the wars, earthquakes and other disasters, will continue much the same. I think there will be more coverage of scientific research, though. It’s already happening in areas that may directly affect our lives, like genetic engineering. In the future, I think there will be more coverage of scientific explanations of why we feel as we do—as we develop a better understanding of how the brain operates and what our feelings really are.

It’s quite possible that in the next century newspapers will be transmitted electronically from Fleet Street and printed out in our own home. In fact, I’m pretty sure that how it will happen in the future. You will probably be able to choose from a menu, making up your own newspaper by picking out the things you want to read--sports and international news, etc.

I think people have got it wrong when they talk about competition between the different media. They actually feed off each other. Some people once foresaw that television would kill off newspapers, but that hasn’t happened. What is read on the printed page lasts longer than pictures on a screen or sound lost in the air. And as for the Internet, it’s never really pleasant to read something just on a screen.

The phrase“feed off”in the last paragraph means()·

A.depend on

B.compete with

C.fight with

D.kill off

题型:选择题

CTOD("04-01-01")+20的结果是______。

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