in bed /on bed /in the bed /on the bed之间有什么区别?快特别强调on bed,

in bed /on bed /in the bed /on the bed之间有什么区别?快特别强调on bed,
in bed /on bed /in the bed /on the bed之间有什么区别?快
特别强调on bed,

in bed /on bed /in the bed /on the bed之间有什么区别?快特别强调on bed,
in bed:卧床
lie on a bed
如:My sister is ill in bed.
我妹妹卧病在床.
on bed:在床上
如:The cat is on bed.
两者主要区别在于前者强调躺着,不方便行走；后者只是陈述某物或某人在床上,强调的是人或物的位置.
关于stay on bed 和stay in bed有什么不同?
这个问题主要在于理解定冠词的意义
定冠词是表特指,生硬的翻译过来就是 "呆在那张床上"
那么从字面看,就看不出在床上做什么.
而没有定冠词,则表明在床上睡觉.
这和英语的表达习惯有关
你习惯就好了

1. go to bed 上床睡觉。如：He goes to bed at nine. 他九点上床睡觉。He didn’t go to bed until his wife came back. 直到他妻子回来他才睡觉。He didn’t go to bed until OR: maroon; FONT-FAMILY: 'Times New Roman'">比较 go to bed(上床睡觉)与 ...

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1. go to bed 上床睡觉。如：He goes to bed at nine. 他九点上床睡觉。He didn’t go to bed until his wife came back. 直到他妻子回来他才睡觉。He didn’t go to bed until OR: maroon; FONT-FAMILY: 'Times New Roman'">比较 go to bed(上床睡觉)与 go to the bed(到床边去)。如：He went to bed at 10 last night. 他昨晚10点钟上床睡觉。He went to the bed and found a letter on it. 他走到床边，发现上面放着一封信。2. in bed 在床上(睡觉)。如：He is still in bed. 他还在睡觉。He’s sick in bed with a cold. 他因感冒而卧床。注：该结构中通常不用冠词或其他限定词。3. make the bed 铺床。如：Make the bed whenever you are up. 起床就要铺床。注：make one’s (own) bed, 意为“自食其果”。如：As you make your own bed, so you must lie on it. 你是自作自受。4. on a (the) bed 在床上。如：There is a red box on the bed. 床上有个红色的盒子。注：该结构通常应有冠词或其他限定词，有时它与 in bed 大致同义，只是搭配不同而已。如：躺在床上看书是个坏习惯。正：It is a bad habit to read in bed. 正：It is a bad habit to read on a [the] bed.

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in bed （人）躺在床上
in the bed （人）躺在床上，特指一张床
[类似于in hospital 和 in the hospital]
on 用于物体

in bed 跟 in the bed 还真不清楚
是不是+the就指了是哪张床?
on 一般指躺