We have a lot of bother finding a vacant apartment.

我们费了不少周折才找到一间空的公寓.

A vacant apartment in New York City is very difficult to find.

在纽约市内很难找到一所空的公寓住处。

Sometimes landlords will reduce your rent for a month if you help them fill a vacant apartment.

有时候如果你帮房主把空房间都填满，他/她说不定会免去你一月的房租。