to understand new concepts or ideas fast
comprendre rapidement de nouveaux concepts ou idées (comprendre rapidement de nouveaux concepts ou idees)
"She catches on quickly when it comes to math problems."
"Elle comprend rapidement quand il s'agit de problèmes de mathématiques." (elle **catch on quickly** quand il sagit de problemes de mathematiques)
to increase a country's foreign currency holdings
to resume something after a break
to exchange ideas, beliefs, or customs with others
to make yourself work harder to achieve something
to make someone feel excited or full of energy
to act together in support of a cause or issue