【单选题】【消耗次数：1】
由一点放射的投射线所产生的投影称为（ ）
①
中心投影
②
平行投影
③
垂直投影
④
正投影
参考答案：
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随机题目
【单选题】
With the popularity of smartphones, the micro blog __________ a good platform for the young to show themselves gradually.
①
becomes
②
has become
③
is becoming
④
became
【单选题】
1. We cant ___ one to change the habits of a lifetime in a short time.
①
hope
②
wait
③
expect
④
imagine
【单选题】
There were dirty marks on her trousers ___ she had wiped her hands.
①
where
②
which
③
when
④
that
【单选题】
EBay, Amazon and WalMart are popular websites ___ people can sell goods to each other.
①
where
②
which
③
when
④
whose
【单选题】
I hope ___ the little ___ I have been able to do has been of some use.
①
that; that
②
/; by which?
③
what; what
④
/; with which
【单选题】
The hours ___ the children spend in their one-way relationship withtelevision people undoubtedly affect their relationships with real-life people.
①
when
②
that
③
in which
④
on which