在劳动作业场所中可能接触的电磁辐射包括非电离辐射、电离辐射，下列电磁辐射中，属于电离辐射的是（）。
A. 紫外线
B. 红外线
C. 激光
D. X射线
Since the introduction of the new technique, the production cost____ greatly.
A. reduces
B. reduced
C. is reducing
D. has been reduced
By the time you get there tomorrow, they___ for Beijing.
A. will have left
B. are leaving
C. will leave e
D. are to leave
A young man stood nearby while I (read) ______the newspaper.
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