I didn't understand
Quelqu'un a dit quelque chose, mais que je n'ai pas compris.
Someone said something, but I didn't understand it.
Je n'ai pas compris la question.
I didn't understand the question.
Je n'ai pas compris ce qui se passait.
I didn't understand what was happening.
Malheureusement, je n'ai pas compris ce que tu as dit.
Unfortunately, I didn't understand what you said.
Je n'ai pas compris ce que Tom voulait dire.
I didn't understand what Tom meant.
Je n'ai pas compris ce qu'il m'a dit.
I didn't understand what he told me.
Tom a dit quelque chose en français que je n'ai pas compris.
Tom said something in French that I didn't understand.