下列气体与空气混合后遇明火，可能发生爆炸的是（ ）
A：氧气
B：氮气
C：一氧化碳
D：二氧化碳
“This is a useful dictionary, I think. " "So it is, and it's __________ unusual one.”
—I told you it would broke easily it was the weakest.
