AutoCAD中要恢复最近一次被删除的实体,应选用______命令。
A.OOPS
B.U
C.UNDO
D.REDO
参考答案:C
The laboratory ________ construction will be completed by the end of this month. [ ]
A. at
B. under
C. for
D. in
稳定态二氧化氯为二元包装的消毒剂,使用前是否应按使用说明书先进行活化。