GIS超声波检测通常选用的检测频率为（），频率较低时灵敏度较高

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问题单项选择题

GIS超声波检测通常选用的检测频率为（），频率较低时灵敏度较高但易受噪声干扰，而频率较高时信号衰减又会增大。

A.10kHz-100kHz

B.10kHz-300kHz

C.1kHz-10kHz

D.100kHz-500kHz

答案

参考答案：A

填空题

单词拼写。

根据下列各句句意和空白之后的汉语提示词，在横线上写出对应单词的正确形式，每空只写一词。

1. As is known to us, Bank of China has many ______(分支机构)all over the country.

2. Newspapers can keep us well ______(知晓的,了解的)about what is happening all over the world.

3. It is very difficult to ________(联系)the result with the unknown cause.

4. They are________(讨论) about the problem with education.

5. Her work has ________(有助于)greatly to our understanding of this difficult subject.

6. The ______(屋顶)of the buildings were broken in the hurricane.

7. We must arrange a ______(方便的) time and place for the meeting.

8. She was strongly ________(推荐)for the post.

9. She doesn't have enough _____(力气)to carry it upstairs.

10. I only caught a ______(一瞥)of the parcel, so I can't guess what was inside it.

问答题简答题

鉴定书的书写是怎样的？