the penny drops
成語所屬單字drop
the penny drops — 慣用語
1. Used to say that somebody has finally understood or realized something that they
1.慣用語
釋義
恍然大悟
Used to say that somebody has finally understood or realized something that they had not understood or realized before.
例句
After a long explanation, the penny finally dropped.
It took a while, but then the penny dropped and she understood.