Question

赖氏英语语法上的选择题：The boys are ______。 A.on upstairs B.in upstairs C.upstair D.upstairs

为什么答案是D，而不能选B，我觉得B没有问题啊。upstairs可以做名词。由介词in+地点名词组成地点副词短语作表语有错吗？？？

Answer 1

upstairs当名词使用的时候，是“楼层”的意思。
N-SING 楼层 The upstairs of a building is the floor or floors that are higher than the ground floor.

Together we went through the upstairs.
我们一起走过各层楼。
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。

The laundry is in the upstairs bedroom.
洗衣间在楼上的卧室里。

Answer 2

本句中的upstairs是副词，所以前面不加介词。下句中的upstairs为名词： They actually moved down from upstairs because the rent's that expensive.他们确实从楼上搬到了楼下，因为房租太贵了。