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问题 选择题

用与丝绸摩擦过的玻璃棒去靠近轻质小物体a，a被吸引过来，则a（       ）

A．带正电

B．带负电

C．不带电

D．可能带负电，也可能不带电

答案

答案：D

题目分析：在此题中涉及了以下三个知识：（1）在物理学中规定：与丝绸摩擦过玻璃棒上所带的电规定为正电。（2）带电体的性质：能够吸引轻小物体。（3）电荷间的相互作用规律：同种电荷相排斥，异种电荷相互吸引。而a又属于轻小物体，玻璃棒带正电，所以a既可能带负电也可能不带电。故选D。

选择题

—Look at the picture .  ________ big watermelon it is!

—Yes. Let’s see how heavy it is .

A．What

B．What a

C．How

D．How a
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单项选择题

Letter A
Dear Rose,
I like your programmes very much. I’m now writing to ask you something about American social customs. My American friends want me to join them in their dinner party. I am very happy and have decided to go, but I’m a little worried about it, too. The social customs in my country are very different from here, so I’m afraid of making mistakes.
Should I bring a present, such as sweets or flowers Should I arrive on time or a little late At the dinner table, how can I know which fork or knife to use How can I let the family know that I’m thankful for their kindness
Wang Lin
Letter B
Dear Wang Lin,
It’s a good idea to bring a small present when you go to a dinner party. Flowers are always nice, or you may bring a bottle of wine if you know that your friends drink it.
You should arrive on time or five to ten minutes late. Don’t get there early. If you’re going to be more than fifteen minutes late, you should call and tell them.
Try. to be free at the dinner table. If you don’t know about choosing the right fork or knife, just watch the other people, and follow them. If you still have no idea of what to do, ask the person next to you.
If you like the food, say so. Of course, you’ll thank them for the meal and for their kindness. It’s also a good idea to send a thank you card the day after.
Rose

Rose is possibly ______.

A. a good housewife
B. a TV hostess
C. a member of the dinner party
D. a friend of Wang Lin’s
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