Tom came in just now; he,s probably upstairs. 是否应为he,s probably in the upstairs?

应为he is probably upstairs.upstairs是副词,可以直接在系动词之后做表语.谢谢， in the upstairs 或者in upstairS什么时候用？什么时候都不用in the upstairs 或者in upstairSupstairs为形容词时，可以和the连用：an upstairs balcony.楼上的阳台upstairs为名词时，可以和the连用：Frances invited them to occupy the upstairs of her home.弗朗西丝邀请他们住在她家的楼上。