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【简答题】
为什么公路要限制坡长？
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参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】数字信号和模拟信号的特点是( )。
A.
模拟信号大小上、时间上均不连续，数字信号则相反
B.
数字信号大小上、时间上均不连续，模拟信号则相反
C.
数字信号、模拟信号大小上、时间上均不连续
D.
数字信号、模拟信号大小上、时间上均连续
【单选题】_______ Tom, we wouldn’t have been late for the last bus.
A.
If we didn’t wait for
B.
If we haven’t waited for
C.
we hadn’t waited for
D.
Had we not waited for
【简答题】We didn't know his telephone number, otherwise we _____ him. (A) would have telephoned (C) would telephone (B) must have telephoned (D) had telephoned
【单选题】We used to have a discussion, ___?
A.
did you
B.
didn’t we
C.
used we
D.
didn't used we
【单选题】--Why didn't you answer the phone this afternoon?--We didn't hear it. I was in the garden and Mum ______ a shower.
A.
has had
B.
had
C.
was having
D.
had been having
【单选题】— You didn't wait for Tom yesterday. — Yes, but we ______. He didn't come. [ ]
A.
needn't have
B.
didn't need to
C.
could have
D.
should have
【简答题】We didn’t go fishing because it rained heavily．（改为同义句） We didn’t go fishing________ ________ the heavy rain．
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