To begin to understand something.
Commencer à comprendre quelque chose. (commencer à comprendre quelque chose)
"It took him a while to catch on to the new rules."
"Il lui a fallu un moment pour comprendre les nouvelles règles." (il lui a fallu un moment pour comprendre les nouvelles règles)
to fail to do what one promised
to discover the main cause of a problem
to surprise or shock someone suddenly
to support or to make a copy of important data
An unintentional mistake that reveals one's true thoughts or...
Having traditional ideas or values; not modern