开了那么久的车，你一定累了——为什么不小睡一会儿？

You must be tired after all that driving - why don't you have a little ___sleep?

他陷入了沉睡。

He fell into a deep ___sleep.

我不知道该怎么办，所以去睡了一觉。

I didn't know what to do, so I went for a ___sleep.