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问题 单项选择题

入户完成后应进行ONU的发送及接收性能测试，以及端到端衰减测试，要求ONU发射光功率-1dBm～4dBm，最小接收光灵敏度为（）dB。

A.-20

B.-22

C.-24

D.-25

答案

参考答案：C

单项选择题

活塞式冷水机组基础施工时，基础浇筑（）天以后，强度达到（）%以上时，方可安装设备。

A、3；40

B、5；50

C、8；55

D、10；60
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单项选择题

I was reading Shirley Hazzard’s novel The Transit of Venus. Though I (51) her other books, I had always resisted this one. It (52) me as too pure somehow, too heroic, larger or finer than life and therefore unreal. But now I read it with an almost (53) pleasure. There were sentences that (54) of gratification to my eyes and (55) the hairs on the nape of my neck. I was in a Boston hospital, propped tip in bed with a feeding tube in my arm after (56) surgery for cancer. It was

(57) double room and my roommate, who (58) when he spoke because he had both a broken chin and a drug habit was spraying the air for the fourth or fifth time that day with (59) had a television set and a radio going (60) . The diagnosis of my case was ambiguous. When I asked the doctor the usual question-How much time have I got—he hesitated before answering. "I would say," he said, "that you have in the neighborhood of years.\

57().

A.a 

B.an 

C.the 

D.these
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