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【简答题】
一个622M光纤通信系统，系统中所采用激光器， 其标称波长为1310nm， 光脉冲谱线宽度λ<=2nm。发光功率为0 dBm。接收灵敏度为－28 dBm。光纤损耗为0.2 dB/Km，光纤色散系数D＝1.8ps/km.nm，问系统所允许的最大中继距离是多少？
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【单选题】I don’t want to use your pen, I want _______.
A.
somebody else’s
B.
somebody’s else
C.
somebody else
D.
somebody’s else’s
【单选题】I don’t want to use the same tool _______ you used yesterday to repair the air conditioner.
A.
it
B.
that
C.
one
D.
what
【单选题】Why wouldn’t the car move one week later?
A.
The car ran out of gas.
B.
The gas tank was broken.
C.
The meter on the front panel was broken.
D.
He broke his car.
【单选题】—Excuse me. But I want to use your computer to type a report. —You _____have my computer if you don’t take care of it .
A.
shan’t
B.
might not
C.
needn’t
D.
shouldn’t
【单选题】Match the use of while with the category it belongs. While I don’t want to make a fuss, I feel I must protest at your interference.
A.
During the time that sth is happening
B.
At the same time as sth is happening
C.
As long as
D.
Although
E.
Whereas
【单选题】--What kind of mobile phone would you like? --Oh, I’d like one with a camera and I don’t want to ________ by cash.
A.
give
B.
pay
C.
use
D.
buy
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