Question

【题目】—Are you sure you have to do this now? It's been very late.

—I don't know to do it if not now.

A. where B. how C. what D. when

Answer 1

【答案】D

【解析】试题分析：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。