There was a big hole in the road which ________ the traffic.

don’t try your best to learn all subjects, youwill ___ behind

we cannot close the gulf between us, we can try to bridge it so that we may be able to talk across it.

下列句子中加横线的词语，能被括号里的词语替换且符合句意的一项是（ ）

(2013·湖南，26)If nothing________，the oceans will turn into fish deserts