当我们到达时，电影结束了。

When we arrived, the film was over.

youdao

当我们到达时，我们发现了这个欢迎我们的社区。

When we arrived we found this community that welcomed us.

youdao

当我们到达苏珊家时，她非常热情。

When we arrived at her house Susan was very welcoming.

《柯林斯英汉双解大词典》

Once we're there, we have to do the merge.

当我们到达这步时。

麻省理工公开课 - 计算机科学及编程导论课程节选

so we know how to do this, and we know this thing when it hit these stops, v2 the pressure with p2, and the volume was V2.

所以我们知道怎么计算，当活塞到达这两个挡板时，压强是p2，体积是。

麻省理工公开课 - 热力学与动力学课程节选