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问题 单项选择题

检查两件产品，记A=“至少有一件不合格”，B=“两件产品检查结果不同”，则事件A与B之间的关系是（）。

A.A

B.B

C.C

D.D

答案

参考答案：A

解析：

设X表示“两件产品中的不合格品数”，X是随机变量，且A={x≥1}，B={X=1}，从而。故答案为选项A。

完形填空

Beijing is the c小题1:of China. It is an old c 小题2:  and there are lots of places of i 小题3:  in Beijing. You know the emperors of Qing Dynasty lived in the Palace M 小题4: . You can walk s 小题5:  around the big lake and feel the b 小题6:  of the old park in the Summer Palace. You can also drink s 小题7:   Beijing tea in Laoshe Tea House. It is also a m 小题8:   city, you can visit the big s 小题9:   in Wangfujing Street and you can travel to the World Park by u  小题10:  .
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单项选择题

For each blank, choose the best answer from the four choices and write down on the answer sheet.

(1) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.

(2) is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.

(3) is an approach preferred by cable TV providers. In this solution the fiber terminates at an optoelectrical converter and the final segment is a shared coaxial cable.

(4) is a device used to connect two separate network that use different communication protocol.

(5) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

5（）

A．NNI

B．NRZ

C．NAK

D．NVT
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