英语可以说in bed，但很少见到on bed的用法。

但我在BNC语料库里查了一下，也可查到部分用例：如：

And I think, I know where they are, I think they're on bed.

She said, when I went round she was sat doing crossword on bed.

The authority spent £18,500 on bed and breakfast accommodation because its existing hostel was full.

但实事求是地说，我没在英语词典上见过此类用法，所以我建议不要把以下各句中的in bed换成on bed：

He lay in bed, awake. 他躺在床上，没有睡着。

Stay in bed for a couple of days. 卧床休息几天。

I was in bed with flu for ten days. 我因患流感，卧床10天。

The doctor ordered her to stay in bed. 医生要求她卧床休息。