等物质的量的下列物质，分别完全燃烧时，消耗氧气最少的是（  ）

A．苯

B．甲烷

C．乙烯

D．乙醇

.

You should remember the cause and avoid it the next time you __________ the same situation.

A．come out

B．come about

C．come up

D．come across