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问题 单项选择题

设信息速率为sbit106/s，则2ASK、2PSK信号的谱零点带宽分别为（）。

A.106bits/s，2X106bit/s

B.106bits/s，106bits/s

C.2X106bit/s，106bits/s

D.2X106bit/s，2X106bit/s

答案

参考答案：D

写作题
假如你是Han Mei，下面是一封你的笔友Alice给你发来的e-mail的内容，给她写一封回信，与她交流看法，并帮她排忧解难。词数在80左右。
提示词： listen to , mother’s love, care about, communicate with, get along with, smile
Dear Han Mei,
I’m afraid I’ve got a big problem recently. My mother talks too much to me. She always tells me, “Be careful while crossing the street.” “Put on more clothes.” “Did you do a good job at school?” and so on. I’m annoyed. What shall I do?
Alice
Dear Alice,
As a teenager, I met the same problem as you.                                                  
                                                                              
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单项选择题

我国对香港地区的铁路运输的特点是（）。

A.直达运输

B.集装箱运输

C.租车方式，两票运输

D.一票运输
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