昨天我在地铁上遇到了一位老同学。

Zuótiān wǒ zài dìtiě shàng yùdào le yí wèi lǎo tóngxué.

Yesterday I ran into an old classmate on the subway.

出国旅行的时候，你可能会遇到很多新问题。

Chūguó lǚxíng de shíhou, nǐ kěnéng huì yùdào hěn duō xīn wèntí.

When traveling abroad, you may encounter many new problems.

在工作中遇到困难时，他总是先冷静下来再想办法。

Zài gōngzuò zhōng yùdào kùnnan shí, tā zǒngshì xiān lěngjìng xiàlái zài xiǎng bànfǎ.

When he encounters difficulties at work, he always calms down first and then thinks of a solution.