67.——Are you sure you have to?It's been very late.——I don't know __c___ I can do it if not now分析

问题描述:

67.——Are you sure you have to?It's been very late.——I don't know __c___ I can do it if not now
分析

when
-你确定你必须要做么,现在太晚了。
-我不知道如果我现在不做该何时去做。

when吧
有if not now的提示
-你确定你必须要做么,现在太晚了.
-我不知道如果我现在不做该何时去做