就在我们准备离开时，一辆公交车来了。

Just as we were about to leave, a bus ___came ___along.

一个陌生人出现并提供了帮助。

A stranger ___came ___along and offered to help.

我们等了几个小时，救援队才到达。

We were waiting for hours before a rescue team ___came ___along.