恍然大悟

huǎng rán dà wù

to see the light suddenly

Character by character

恍huǎng
suddenly

然rán
so

大dà
greatly

悟wù
realise

听了他的解释，我才恍然大悟。

Only after his explanation did it finally click for me.

Tone: neutral.

Usually with 才 or 这才, after whatever triggered the realisation.

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