他的表情很复杂。
tāde biǎoqíng hěn fùzá 。
His expression is very complicated.
老师用表情来帮助学生理解。
lǎoshī yòng biǎoqíng lái bāngzhù xuéshēng lǐjiě 。
The teacher uses expressions to help the students understand.
她的表情让我知道她很开心。
tāde biǎoqíng ràng wǒzhīdào tā hěn kāixīn 。
Her expression made me know that she is very happy.