She walked across the floor and lay down on the bed.

她走过地板躺在了床上。

《柯林斯英汉双解大词典》

She lay on the bed, her arms and legs splayed out.

她四肢摊开躺在床上。

《牛津词典》

I lay down on the bed with my shoes off to have a snooze.

我脱了鞋，躺在床上打个盹儿。

《柯林斯英汉双解大词典》

Later that day, Sue came to the bed where Johnsy lay, and put one arm around her.

VOA: special.2009.08.01

So you would say in the past tense "I lay on the bed because I was tired."

VOA: special.2010.02.11

His head began to ache, and Mister Mindon lay down on the bed.

VOA: special.2010.05.29

He said Gilliard had got the statue from the garden and the knife from the kitchen before going upstairs to attack his wife in the bedroom as she lay on the bed.

BBC: Frederick Gilliard jailed for killing wife with statue

It was only when I got home at midnight and lay on the bed with my sleeping five-year-old daughter that the tension of the day gave way to fear of what was to come.

BBC: Remembering the Pentagon attack

She lay down on the bed, her feelings concentrated at the forefront of her mind like an immensely weighted black point, incomprehensible.

NEWYORKER: In Other Rooms, Other Wonders