问题 不定项选择

如图所示,在电场中,一个负电荷从C点分别沿直线移到A点和B点,在这两个过程中,均需克服电场力做功,且做功的值相同,有可能满足这种做功情况的电场是

[ ]

A.正y方向的匀强电场

B.正x方向的匀强电场

C.在第Ⅰ象限内有负点电荷

D.在第Ⅳ象限内有负点电荷

答案

ACD

阅读理解

阅读理解。

     It's important to prepare(准备) for earthquakes because you don't know where you will be when an

earthquake happens. Earthquakes may happen at any time, so prepare some things for your home, office

and car.

     1. Clothes.

     If you live in a cold place, you must keep warm. You might not have heat after an earthquake. Think

about your warm clothes.

     2. Flashlights (手电筒) and spare batteries.

     Keep a flashlight beside you bed, at your office and in your car. Do not use matches (火柴) after an

earthquake until you are sure that no gas leaks (气体泄漏).

     Prepare a radio and some spare batteries. Most telephones will be out of order, so radios will be your

best source of information (信息来源).

     3. Food and medicine.

     It's always a wonderful idea to keep some food on hand. For example, some biscuits, some canned

food, milk and some other drinks for at least 72 hours. You'd better get some necessary medicine for

your family.

     4. Water.

     A person needs at least 1/2 gallon (加仑) of water daily just for drinking. Store at least 1 gallon of

water for a person every day and be prepared for 72 hours. It is suggested that you buy bottled water.

Do not open the bottle until you need it. Also, do check the "use by" date.

1. Why should people prepare themselves for an earthquake?

A. Because earthquakes can be know before they happen.

B. Because earthquakes usually take place in the neighborhood.

C. Because we don't know when and where an earthquake will happen.

2. If you live in a cold place, you should prepare _____.

A. some hot water

B. some warm clothes

C. some batteries

3. According to the article we know that _____.

A. we need to prepare some things only at home

B. a telephone is the most important source of information

C. flashlights but not matches are first used after earthquakes

4. You should prepare all of the following except _____.

A. milk

B. fresh vegetables

C. biscuits

5. About the water, which description is RIGHT?

A. A person should drink at least 1 gallon of water in a day.

B. You shouldn't open the bottled water until you need it.

C. You'd better keep some hot water for 72 hours.

单项选择题