He fell into a deep dreamless sleep.

他酣然入睡，一夜无梦。

《柯林斯英汉双解大词典》

On this occasion, he had fallen at once into a dreamless sleep.

这一次，他立刻进入了无梦的睡眠。

youdao

I can picture being in dreamless sleep quite easily.

我能够轻而易举地想象无梦的睡眠。

youdao

Suddenly I was in deep,dreamless, peaceful sleep.

VOA: special.2010.07.10

But think of the various periods during the night in which you are in a deep, deep dreamless sleep.

但请设想你处在这样的夜晚,你处于熟睡，安枕无梦。

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From the mere fact that they can't picture it from the inside, it doesn't follow that nobody believes they're ever in dreamless sleep.

仅从他们无法设身处地,想象这种情况这个事实，是无法得出没有人相信,自己能处于无梦睡眠的结论的。

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