"在医院" 在英语中可以表达为 "in the hospital"。

来源：

"In" 是一个介词，意思是"在……里面"。"The" 是定冠词，意思是"那个"。"Hospital" 是名词，意思是"医院"。

英文例句及其中文翻译：

I'm going to be in the hospital for a few days. (我要住进医院几天。)
My grandma has been in the hospital for a week. (我奶奶住进医院已经一周了。)
I work in the hospital as a nurse. (我在医院当护士。)