Mr Smith asked ____off because he didn't feel well.

问题描述:

Mr Smith asked ____off because he didn't feel well.
A.three day B.three days C.three days' D.three-day
为什么答案是B,不是选D作形容词吗?

three-day这种词只作定语,修饰后面的名词,而off不是名词.
请假的表达法:ask for three days' leave,ask(for) three days off