Definition: used to say at what time something happened or will happen Level: A2
当你准备好的时候，我们就去公园。
We'll go to the park ___when you're ready.
我在打扫房间时发现了我的老照片。
I found my old photos ___when I was cleaning my room.
当大家都就座后，电影就开始。
The movie starts ___when everyone is seated.
