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问题 填空题

科学工作者为了测海底某处的深度，向海底垂直发射超声波，经10秒后收到回声，已知声音在海水中的传播速度为1500m/s，则该处海水的深度为______m，这种方法______（能/不能）用来测量月球到地球的距离，因为______．

答案

（1）超声波从海面传到海底的时间：

t=

1
2
×10s=5s，

海洋的深度：

h=s=vt=1500m/s×5s=7500m；

（2）月球在大气层外，没有空气（是真空），声音在真空中不能传播，所以这种办法不能测量月球与地球之间的距离．

故答案为：7500；不能；声音不能在真空中传播．

阅读理解

任务型阅读(10分)

It is very important to have good friends. 1)拥有许多朋友的一种生活是有趣且丰富多彩的。A life without a friend is a life without a sun.2)Having good       can       us in lots of different ways. People with a lot of friends usually feel happier than people with no friends. Everything we do will be more fun if we have friends with us to share our adventures(经历). When we are feeling sad or worried, our friends will give us advice and help us out of difficulties.

We should not only have good friends but also be good friends. We need our friends as much as they need us. We should be willing to help friends when they need help.

1. 回答下面问题

What will friends do when we are feeling sad or worried?

                                                                   

2. 在2)句的空白处填入适当的词使句意完整、上下文通顺：                

                                                                     

3. 将1)句译成英语：____________________________________________________

4. 写出文中与下列句子意思相近的句子：

If friends need our help, we should be glad to help them.

_____________________________________________________________________

5. 找出文中最能表达该短文主题的句子：                                

______________________________________________________________________
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问答题 简答题

应答器安装角度是如何规定的？
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