영어로 "be quick on the uptake"의 정의와 의미

During the training session, John proved to be quick on the uptake. He learned the software's features and functionality in no time.

In the business meeting, Sarah demonstrated her ability to be quick on the uptake by comprehending complex data and proposing innovative solutions.

He's been working on that math problem for hours and still has n't figured it out. He's definitely slow on the uptake when it comes to complex calculations.

I had to explain the joke to him three times before he finally got it. He's a bit slow on the uptake.