Grammar fix

catch up on

do something you missed earlier

to do work, tasks, or activities that you could not do before because you were busy or away.

phrasal verbB1common

Hear it in context

Notice where the phrase sounds natural.

After my holiday, I had to catch up on all my emails at work.daily life
If I miss a few classes, I usually spend extra time at home to catch up on my studies.IELTS speaking

Pattern: catch up on + noun/gerund

WrongI need to catch up my sleep.

RightI need to catch up on my sleep.

'Catch up ON something'.

Patterncatch up on + noun/gerund

Choose the version that sounds natural in speech.

Stiff I must attend to the accumulated correspondence I previously failed to address.

Natural I need to catch up on my emails.

'Attend to accumulated correspondence' is bureaucratic; 'catch up on' is natural.

Words that usually travel with it.

'Catch up with' is used for meeting or talking with people, while 'catch up on' is for tasks or things you need to do.