to bed的意思是“上床”、“就寝”,bed之前不能加定冠词the,也不能加this、that、your、my等词,因为它是固定词组.例：
When did you go to bed last night?
昨晚你几点钟上床?
I usually go to bed at eleven．
我通常十一点就寝.
go to sleep的意思是“入睡”、“睡着”.因此,go to bed并不等于go to sleep. 如所周知,一个失眠的人往往在go to bed之后过了很久也不能 go to sleep. 例：
Last night I was too excited to go to sleep．
昨晚我激动得不能入睡.
I went to sleep at two this morning!
今晨两点我才睡着.
现将 go to bed和go to sleep用在一个句中,以便区别：
She usually goes to bed at nine and goes to sleep a few minutes afterwards．
她通常九点上床,几分钟后就入睡.
