by which time英语问题

问题描述:

by which time英语问题
4.Lucy and I made an appointment of an interview on Sunday afternoon,_______________  (到那时) I would be free.
by which time
好奇怪的
by which time不是在这之前么

by which time 确实是 在····之前的意思.
这句话的意思是,
我和lucy在周六下午有个会面,在那之前我都有时间,
言下之意是 他无法参加那个会面,因为周六下午没时间