ph.

1. 赶上;追上;跟上
If you catch up with someone who is in front of you, you reach them by walking faster than they are walking.

2. 赶上，达到(标准、水平等)
To catch up with someone means to reach the same standard, stage, or level that they have reached.

3. 补做;赶做
If you catch up on an activity that you have not had much time to do recently, you spend time doing it.

4. 了解近况;叙旧
If you catch up on friends who you have not seen for some time or on their lives, you talk to them and find out what has happened in their lives since you last talked together.

5. 牵扯进;卷入
If you are caught up in something, you are involved in it, usually unwillingly.

1. learn belatedly
find out about something after it happened

e.g. I'm trying to catch up with the latest developments in molecular biology

2. reach the point where one should be after a delay

e.g. I caught up on my homework