Question

Learning to write is learning to think. You don’t know things clearly _________ you can write
them down.

A．unless

B．if

C．since

D．whether

Answer 1

A

解析试题分析：句意：学习写作就是学习思考。你不能清楚地知道事情除非你可以把他们写下来。Unless除非；if如果； since从；whether是否。所以选A。
考点：考查连词。