句中时间状语前为什么用介词for
问题描述：
句中时间状语前为什么用介词for
He then asked when Mr Gilbert would be allowed to go home and the doctor told him that he would have to stay in hospital for another two weeks.
答
用for表示这个时间段,时间上通常用介词for,本句就是：他得再多呆在医院两周,而不用for,则表示具体的时间点