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问题 单项选择题

在数字传输系统中受延迟影响最大的是 (60) 。

A．低速模拟信号

B．低速数字信号

C．高速模拟信号

D．高速数字信号

答案

参考答案：D

解析：[分析] 在数字传输系统中受延迟影响最大的是高速数字信号。

完形填空

根据对话情景和内容，从对话后所给的选项中选出能填人每一空白处的最佳选项，并在答题卡上将该选项涂黑。选项中有两个为多余选项。

Repairman: Good afternoon_____小题1:___

Customer: Hello. My mobile phone isn’t working. Could you repair, please？

Repairman: __小题2:__

Customer: It worked well yesterday, but I simply couldn’t turn it on this morning.

Repairman: __小题3:__

Customer: Here you are.

Repairman: Well，I think we’ll be able to fix it. You can pick it up this Friday.

Customer: Oh, no. That’s too long. _小题4:___I need it as soon as possible.

Repairman: Let me see. How about Wednesday afternoon?

Customer: __小题5:__What time?

Repairman: After five o’clock

Customer: Ok. Thank you.

A．That’s great.

B．I beg your pardon?

C．Let me have a look.

D．What’s the problem?E. I’m sorry to hear that.        F. What can I do for you?

G. I wonder if you could fix it earlier.
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多项选择题

下列关于灌注桩具体适用的条件正确的是( )。

A．适宜的地基持力层位置较深

B．河床冲刷较大，河道不稳定

C．当地基计算沉降过大或结构物对不均匀沉降敏感时

D．施工水位或地下水位较低时

E．采用浅基础或人工地基在技术上、经济上不合理时
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