the penny drops

US /ðə ˈpɛni drɑps/
UK /ðə ˈpɛni drɑps/
"the penny drops" picture
1.

akhirnya faham, sedar

used to say that someone has finally understood something, especially after a period of not understanding

:
It took him a while, but then the penny dropped and he realized his mistake.
Dia mengambil sedikit masa, tetapi kemudian dia akhirnya faham dan menyedari kesilapannya.
I kept explaining, but it wasn't until I drew a diagram that the penny dropped.
Saya terus menjelaskan, tetapi hanya apabila saya melukis rajah barulah dia akhirnya faham.