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如下命令将“产品”表的“名称”字段名修改为“产品名称”ALLER TABLE产品RENAME 【15】 名称TO产品名称

答案

参考答案：COLUMN

解析：[知识点] SQL的数据定义功能：ALTER TABLE-SQL[评析] 修改表结构的命令ALTER TABLEA格式： ALTER TABLE TabteNamel [DROP[COLUMN]FieldName3] [SET CHECK 1Expression3 [ERROR cMessage Text3]] [DROP CHECK] [ADD PRIMARY KEY eExpression3 TAG TagName2 [FOR 1Expression4]] [DROP PRIMARY KEY] [ADD UNIQUE eExpression4[TAG TagName3[FOR 1Expression5]]] [DROP UNIQUE TAG TagName4] [ADD FOREIGN KEY[eExpression5]TAG TagName4[FOR 1Expression6] REFERENCES TableName2[TAG TagName5]] [DROP FOREIGN KEY TAG TagName6[SAVE)) [RENAME COLUMN FieldName4 TO FieldName5] [NOVALIDATE] 该格式可以删除字段、可以修改字段名，可以定义、修改和删除表一级的有效性规则等。

阅读理解

The surprising experiment I am about to describe proves that air is all around you and that it proves down upon you．Air pressure is a wonderful force．When you swim underwater, you can feel water push down your body．The air all around you does the same．However, your body is so used to it that you do not notice this．The pressure is caused by a layer of air called the atmosphere．This layer surrounds the Earth, extending to about five kilometers above the Earth's surface．

The following experiment is an easy one that you can do at home．But make sure that you are supervised, because you will need to use matches．

What you need

·A hard-boiled egg without the shell

·A bottle with a neck slightly smaller than the egg

·A piece of paper

·A match

Method

1）Check that the paper will sit firmly on the neck of the bottle．

2）Tear the paper into strips and put the strips into the bottle．

3）Light the paper by dropping a burning match into the bottle．

4）Quickly sit the egg on the neck of the bottle．

Result

Astonishingly, the egg will be sucked into the bottle．Your friends will be amazed when you show them the experiment．But be careful when you handle matches．

Why it happened

As the paper burns, it needs oxygen and uses up the oxygen （air）in the bottle．The egg acts as a seal in the neck of the bottle, so no more air can get inside．This reduces the air pressure inside the bottle．The air pressure must equalize, so more air from outside must enter the bottle．The outside air presses against the egg and then the egg is pushed into the bottle! That proves that air is all around and that it is pressing down on it．

小题1:Why is there the need to take care when you are doing the experiment?

A．The bottle could break．

B．You need to light the paper with a match．

C．The egg needs to be shelled．

D．The egg has to be perfectly placed on the neck of the bottle．小题2:In the experiment, the burning inside the bottle can__．

A．equalize the air pressure inside and outside

B．make a seal in the neck of the bottle

C．finish up the oxygen inside the bottle

D．produce more oxygen inside the bottle小题3:How did the egg put into the bottle?

A．The oxygen inside the bottle sucked the egg in．

B．It became salt without the shell．

C．The neck of the bottle was wide enough．

D．The outside air pressure forced it into the bottle．小题4:The experiment is carried out to prove ____．

A．water pushes on your body when you swim underwater

B．the earth is surrounded by a layer of air called the atmosphere

C．the pressure of air around us has a powerful force

D．the air pressure is not equalized around us
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触电急救，首先要使（）迅速脱离（），越快越好。因为（）作用的时间越（），伤害越重。
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