下列气体与空气混合后遇明火不会发生爆炸的是[ ]
A．氢气
B．甲烷
C．氮气
D．一氧化碳
答案：C
There are only ____ new words in the passage, but I know _____ of them. [ ]
A. a few; none
B. a little; none
C. little; all
D. few; all
历史上的监察制度有哪些共性特征？
