spare room

基本解释

We were able to bunk(down) in a spare room for the night.
我们可在备用房间睡觉过夜。
A spare room, with a couch and a couple of easy chairs, plus a large enough flat-panel television and a reasonable audio system, can more than meet most family’s viewing needs.
在一个空房间放上个沙发和两三个椅子，加上一个足够大的平板电视机和不错的音响设备，已经可以满足大部分家庭的需要。
I talked it over with my mom, and she doesn't have a big place, but there's a spare room, and she's really nice.
我和我妈妈谈过了，虽然她没有大房子，但是有一个空闲的房间，而且她真的很好。

For the flyer with too much spare room in their carry-on, we propose the Cup Pilot.
ECONOMIST: Business travel