2 sentences

1. 听了他的解释，我才恍然大悟。

   tīng le tā de jiě​shì, wǒ cái huǎng​rán​dà​wù.

   It wasn't until I heard his explanation that I suddenly understood.

   Source: Dong Chinese Dictionary

2. 经他这一提醒，我才恍然忆起去年的往事。

   jīng tā zhèi yī tí​xǐng, wǒ cái huǎng rán yì qǐ qù​nián de wǎng​shì.

   With his reminder, I suddenly recalled the events of last year.

   Source: Dong Chinese Dictionary