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【单选题】
在光通信中，若光纤上承载的是波长为1490nm的光信号，每公里的损耗大概是：()A.
0.72dB
B.
0.36dB
C.
0.18dB
D.
0.90dB
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皮皮学刷刷变学霸
举一反三
【单选题】The Chinese food in the United State is usually______ for American people.
A.
exchanged
B.
alternated
C.
modified
D.
cooked
【单选题】---Can you tell me by whom the speech next Friday? ---Mr. Green, our geography teacher.
A.
is given
B.
be given
C.
will give
D.
will be given
【简答题】白族平坝住房多为瓦房,布局一般多为( )。
【单选题】以下哪些是同步器的作用( ) a.使接合套与待接合齿圈两者之间能迅速同步 b.阻止在同步之前轮齿进行啮合 c.阻止接合套与待接合齿圈啮合 d.防止产生结合齿圈之间的冲击
A.
abd
B.
abc
C.
cbd
D.
acd
【单选题】The Chinese food in the United States is usually ______ for American people.
A.
exchanged
B.
alternated
C.
modified
D.
cooked
【单选题】The Chinese food in the United States is usually _______ for American people.
A.
exchange
B.
altered
C.
modified
D.
cooked
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