2013年4月16日18时44分，在伊朗哈什发生7.8级地震，导致很多房屋_爱下问搜题

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问题选择题

2013年4月16日18时44分，在伊朗哈什发生7.8级地震，导致很多房屋坍塌，场景惨不忍睹，就此事件，下列说法正确的有(　　)

A．所有建筑物周期相同

B．所建筑物的振动振幅相同

C．所有建筑物均做自由振动

D．所有建筑物振动能量相同

答案

答案：A

题目分析：地震属于机械波，所以波在传播过程中所有质点的振动周期和波源的周期相同，故A正确，由于地震属于阻尼振动，所以离震源越远，振幅越小，能量越小，故BCD错误

故选A

点评：阻尼振动在传播过程中能量越来越小，振幅越来越小，

多项选择题

（）属于管壳式换热器完好标准内容。

A、检修计划准确

B、操作记录齐全

C、检修记录齐全

D、静密封点无泄漏

补全对话，情景问答

从方框中选择恰当的句子补全对话。

A. If we have today, half the class won't come.
B. Can you organinze the party games?
C. Will you help me organize it?
D. We can all meet and watch a video.
E. Let's have it today after class.

A: Hi, Mark. I want to have a class party. 1
B: Sure, Andrew. I can help you. When shall we have the party?
A: 2
B: No, today is too early. 3
A: Then let's have it tomorrow.
B: But there is a test tomorrow.
A: OK, let's have it on Saturday afternoon. 4
B: No, I don't think we should watch a video. Some students will be bored.
    Let's play party games.
A: OK, good idea. 5
B: Sure. I can do that.