什么情况下用 be in bed?什么情况下用stay in bed?

什么情况下用 be in bed?什么情况下用stay in bed? Marry has a bed cold.She has to stay in 【 】bed.该用什么冠词么 Will she be hot in two days?再什么情况下用 “be”? 什么情况下BE动词用be? During my stay in bed和during i stay in bed有什么不同 哪个对 stay in bed 和stay in the bed 有什么不同? 类似 there is no people in the earth 什么情况下必须用there be 结构?、 must stay in bed stay in bed remain in bed,be in bed,stay in bed的区别 be动词什么情况下 用原形 be in need of sth,和做动词的need,有什么区别,个在什么情况下用,