HSK 1
Wǒ zuótiān pèngdào le yí ge lǎo tóngxué.
I ran into an old classmate yesterday.
HSK 2
Pèngdào wèntí jiù wèn lǎoshī.
If you encounter a problem, ask the teacher.
HSK 2
Zuótiān wǒ zài chāoshì pèngdào le yí wèi lǎo tóngshì.
Yesterday I ran into an old colleague at the supermarket.