--Why didn't you turn up at the meeting?--Ifor a long-distance call from my cousin in England.
A. waited
B. am waiting
C. was waiting
D. have been waiting
查看答案
The naughty boy! Hewhere he leaves his things.
A. always forget
B. will always forget
C. is always forgetting
D. has always forgotten
点的正面投影到ox轴的距离，等于空间点到面的距离
A. H
B. V
C. W
点的水平投影到OX轴的距离，等于空间点到面的距离
A. H
B. V
C. W
点的侧面投影到OZ轴的距离，等于空间点到面的距离
A. H
B. V
C. W
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