猪猪侠xtt
回答你的第一个问题：
He works in a hospital. (which means is job is working in a hospital)
He is working in a hospital. (which means he is working right now)
His work is in a hospital. (unusual expression)
He worked in the hospital. (which means he worked in the hospital in the past)
He works at a hospital. (at is okay but unusual in this situation)
回答你的第二个问题：
In hospital is a British expression while in the hospital is an American expression. Both expressions are okay.
如果你要参加高考，在高考之前，请忽略以上内容，并记住中国人给它赋予的意义：
In hospital 表示住院
In the hospital 表示在医院办事等（除了住院之外的一切事务）
jason大魔王
下面6个句子He works in a hospital。对 他在一家医院工作。He is work in a hospital 错He work is in hospital 错He worked in the hospital 对 他以前在那一家医院工作。He works at a hospital. 可以。他在某一家 小 医院工作。hospital前面加a还是the ，取决于上下文。 如果这个医院 没有上下文提到过， 谈话的双方也都不知道这个医院， 仅仅是 泛泛而谈的 某一家医院， 可以用 a hospital. 上下文提到过的那一家医院 或者双方都知道的那一家医院， 就用 the hospital。宝贝勤学好问， 天天进步！
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