go to sleep: 入睡;去睡觉1.I told them to be quiet and go to sleep .我叫他们不要说话，马上去睡觉。

2.Her mind being in a tumult, she could not go to sleep.她心潮翻滚，无法入睡。go to bed: 去睡觉吧1.Go to bed. You look tired out. 去睡觉吧，你看上去（已是）满脸倦意。