Question

【题目】— Are you sure you have to do this now? It's been very late.
— I don't knowto do it if not now.
A.where
B.how
C.what
D.when

Answer 1

【答案】D
【解析】句意; －你确信你现在必须做吗？很晚了。－如果现在不做, 我不知道何时做。A.where在哪儿, 指地点; B.how怎样, 指方式; C.what什么, 指事物; D.when何时, 指时间。由now可知本空指时间。故选D。