我可以向你兑换一些零钱吗？

Wǒ kěyǐ xiàng nǐ duìhuàn yìxiē língqián ma?

Can I exchange currency with you?

你明天要记得去机场兑换外币。

Nǐ míngtiān yào jìde qù jīchǎng duìhuàn wàibì.

Don't forget to go to the airport tomorrow to convert foreign currency.

我想把支票兑换成现金。

Wǒ xiǎng bǎ zhīpiào duìhuàn chéng xiànjīn.

I'd like to convert a check to cash.