英语可以说in bed,但可以说on bed吗?比如以下各句中的in bed可以换成on bed吗?
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。