where'sJimmyhe'sinbed为什么bed前面不加the

Question

where's Jimmy
he's in bed为什么bed前面不加the

Answer 1

in bed 表示“躺在床上、卧病在床”，短语中的bed不指具体的床，故前在不用冠词，in也不能改成on。
　e.g.
Do I have to stay in bed all day? 我必须整天呆在床上吗？
　 Reading in bed is bad for your eyes. 躺在床上看书对你的眼睛有害。
in the bed:表示在床里面，即在被窝里。
e.g.
I was so tired and wanted to sleep in the bed right now.
"我太累了,真想马上躺在被窝里睡觉"