2 sentences for 同居 (tóng​jū — cohabit)

1. 她知道你们同居了吗？

   tā zhī​dào nǐ​men tóng​jū le ma?

   Does she know you're living together?

   Source: OpenSubtitles

2. 他们在结婚前已经同居了两年。

   tā​men zài jié​hūn qián yǐ​jīng tóng​jū le liǎng nián.

   They lived together for two years before getting married.

   Source: Dong Chinese Dictionary