（）准备越充分，修理的质量和修理进度越能得到保证。
A.修前
B.拆卸
C.清洗测量
D.装配调整
参考答案：A
When asked why he went there, he said he was sent there _____ for a space flight. [ ]
A. training
B. being trained
C. to have trained
D. to be trained
电磁污染的来源有哪些？
