已知集合M={x∈N|(8-x)∈N},则M中元素的个数是[ ]
A.10
B.9
C.8
D.无数个
答案:B
—May I smoke here? —If you _____, choose a seat in the smoking section.
A.should
B.could
C.may
D.must
油田公司HSE管理目标是什么?