spare room

基本解释

We were able to bunk(down) in a spare room for the night.
我們可在備用房間睡覺過夜。
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.
在一個空房間放上個沙發和兩三個椅子，加上一個足夠大的平板電眡機和不錯的音響設備，已經可以滿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.
我和我媽媽談過了，雖然她沒有大房子，但是有一個空閑的房間，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