311A泵吸式可燃气体测爆仪,测量范围采用0~100%的爆炸限,当仪器指针指示到100%时,表示空气中的天然气含量为()
A.5%
B.15%
C.100%
D.0
参考答案:A
. ---- Excuse me, Madam. I wonder if this bus goes to the East Lake?
---- ___________. You should take Bus No. 521.
A.Sure, it does
B.No, it isn’t
C.Oh, sorry, I’m afraid not
D.What a pity! It’s not true
何谓男性不育症?其病因有哪些?