碰到 + Noun/Clause
碰到 (pèngdào) means "to encounter," "to run into," or "to bump into" and describes an unexpected meeting or coming across something. It is a colloquial and commonly used verb for chance encounters with people or situations.
昨天我在超市碰到了老同学。
Zuótiān wǒ zài chāoshì pèngdào le lǎo tóngxué.
Yesterday I ran into an old classmate at the supermarket.
你要是碰到不会的题,可以问我。
Nǐ yàoshi pèngdào bú huì de tí, kěyǐ wèn wǒ.
If you come across a problem you can't solve, you can ask me.
出门碰到下雨,我没带伞。
Chūmén pèngdào xiàyǔ, wǒ méi dài sǎn.
I ran into rain when I went out, and I didn't bring an umbrella.