on the bed, in the bed, in bed有何区别?

on the bed, in the bed, in bed有何区别?
on the bed, in the bed, in bed有何区别?

on the bed, in the bed, in bed有何区别?
on the bed 没有睡着,或者在床上但是没有躺下
in the bed 睡着了,或者是躺在床上,特别是在床上呆了一阵子了.（因为英英字典的解释是：after a very lengthy period of time）
in bed尤指在行房过程中或者在床上做事的过程中.比如：He performs well in bed.又如：Jack and Jane had breakfast in bed.

第一个是在睡觉而且是睡着了，第二个是在床上，不一定睡着。第三个不知道。