Subject + 交换 + 了 + Object
The verb 交换 (jiāohuàn) means "to exchange" and describes the mutual giving and receiving of something between two parties. It combines 交 (to hand over) with 换 (to swap). Common objects include 意见 (opinions), 礼物 (gifts), and 眼神 (glances), as in 交换了眼神 (exchanged glances).
我们交换了联系方式,以后保持联系。
Wǒmen jiāohuàn le liánxì fāngshì, yǐhòu bǎochí liánxì.
We exchanged contact information to keep in touch in the future.
圣诞节的时候,大家互相交换礼物。
Shèngdànjié de shíhòu, dàjiā hùxiāng jiāohuàn lǐwù.
At Christmas, everyone exchanges gifts with each other.
两人交换了一个意味深长的眼神。
Liǎng rén jiāohuàn le yí ge yìwèi shēncháng de yǎnshén.
The two exchanged a meaningful glance.