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【单选题】
以下关于物理层基本概念的描述中错误的是A.
OSI参考模型的最底层
B.
为通信的主机之间建立、管理和释放物理连接
C.
实现比特流的透明传输
D.
数据传输单元是字节
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反馈参考答案：
举一反三
【简答题】《DB11/945-1012》落地式脚手架必须铺设垫板或底座，其底面标高宜高于自然地坪50～100mm，垫板厚度不小于50mm，单块垫板上应设不少于（）根立杆。
【单选题】Who do you suggest _______in charge of this matter? [ ]
A.
is
B.
will be
C.
that is
D.
be
【单选题】No matter who you are or where you come from, one thing is certain: you are acquainted with the mosquito(蚊子)—although you probably wish you weren t. Mosquitoes are everywhere. They can be found all ov...
A.
don' t like mosquito but it is always there
B.
know mosquito and wish them well
C.
wish all the mosquito disappeared
D.
want to be friendly to mosquito but fail at last
【单选题】Cheer up! No matter how ________ you progress, you are ahead of those who never tried.
A.
slowly
B.
quickly
C.
bravely
D.
willingly
【单选题】泡沫灭火系统是采用泡沫液作为灭火剂，主要用于扑救( )。
A.
固体表面和电器设备火灾
B.
非水溶性可燃液体火灾
C.
图书馆珍藏室火灾
D.
底层设置商业服务网点的住宅火灾
【单选题】( )--1________? --I have a headache. A What ’ s the matter? B Where are you ? C Who are you ? D What are you doing ?
A.
What’s the matter?
B.
Where are you ?
C.
Who are you ?
D.
What are you doing ?
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