I have to be in bed by ten o'clock.这句中 by ten o'clock是什么意思,为什么不是at,have to be in bed 是什么句型.
问题描述:
I have to be in bed by ten o'clock.
这句中 by ten o'clock是什么意思,为什么不是at,have to be in bed 是什么句型.
答