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？
