Question

—How long does it take to get to the airport?
—Forty minutes. But it’s foggy today. I’m not sure          the highway will closes soon. Let’s set off earlier

1. A.
   whether
2. B.
   when
3. C.
   how
4. D.
   why

Answer 1

A
疑问词辨析。Whether是否；when什么时候；how如何，怎样；why为什么。句意：到达机场要花费多长时间？——四十分钟。但是今天有雾。我不确定告诉是否不久就要关闭。让我们早点出发吧！结合语境可知选A。