before five o'clock是时间短语,而且不是时间段,而是时间点,因此应该用when提问。
英语对时间的提问重要有一下几种方式:
(1)对时间点提问:what time或者when:
What time do you get up in the morning? 你在早上几点起床?
What time is it now?现在几点了?
(2)对时间段提问:since when
Since when have you lived here?Since two years ago.
你什么时候就住在这里了?从两年前。