跟得上to be able to catch up with

• 你们先走，我们赶得上你们。

  You lot go first. We'll be able to catch up with you.

• 你的功课赶得上他吗？

  Is your school work as good as his?

来得及to be able to do something in time

• 离开车还有半小时，你现在去，还赶得上跟他们告别。

  The bus doesn't leave for another half hour. If you go now you'll have time to say goodbye to them.

参见：赶上