in bed的意思是： 臥床，在床上，睡著，當和 ill 連用時候才指“抱病在床”。
on the bed的意思是：在床上，指人時候，指沒有睡著，或者在床上但是沒有躺下。指物時候，指在床上放著。 擴展資料
on the bed：
1、She walked across the floor and lay down on the bed
她走過地板躺在了床上。
2、He set him on the bed and rubbed him down with a coarse towel
他讓他躺到床上，用壹條粗糙的.毛巾給他擦幹了全身。
3、The tired traveller fell back on the bed and at once fell asleep.
那個疲勞的旅客往床上壹倒就睡著了。
in bed：
She would be in bed by now, as like as not.
這工夫她很可能睡了。
It's time the kids were in bed.
孩子們該睡覺了。
The doctor said I had to stay in bed.
醫生說我必須臥床休息。