He is very quick to catch on to things.

他领悟能力很强。

I didn't catch on to this joke.

我没明白这个笑话。

Sometimes I don't catch on to your jokes.

有时我真的无法理解你的笑话。

He didn't catch on to what you had implied.

他没有理解你话中隐含的意思。

Mothers catch on to what their children think about.

妈妈最理解她们的孩子们在想什么。