Phono-semantic — one part hints at the meaning, another at the sound
Example phrases
我碰巧在机场遇见了那位多年未联系的教授。Wǒ pèngqiǎo zài jīchǎng yùjiàn le nà wèi duō nián wèi liánxì de jiàoshòu.I happened to meet that professor at the airport after many years without contact.
我去超市的时候,碰巧遇到了老同学。Wǒ qù chāoshì de shíhou, pèngqiǎo yùdào le lǎo tóngxué.When I went to the supermarket, I happened to run into an old classmate.
他打电话来的时候,我碰巧在家。Tā dǎ diànhuà lái de shíhou, wǒ pèngqiǎo zài jiā.When he called, I happened to be at home.