catch up on
InseparableThe verb and particle never split. The object always follows the whole phrase.
How to say it
Main stress lands on the first particle: catch UP on. The trailing “on” reduces almost to nothing — expect a schwa, not a full vowel.
Link across the gap. The final /tʃ/ of “catch” moves onto the particle and starts its syllable: “catch up” is said “ca-tchup”. Pausing between the words is what makes phrasal verbs sound recited rather than spoken.
What it means
To do work or rest that you are behind on.
- “I spent Sunday catching up on emails.”
- “She's catching up on sleep after three nights of deadlines.”
Similar: make up