dà sì

ㄉㄚˋ ㄙˋ

Num

1fourth year of university

bù zhī不知dào道nín您shì fǒu是否hái还jì记dé得wǒ我，wǒ我shì是céng曾zài在dà sì大四xiū修guò过nín您jǐ几mén门kè课de的xiào yǒu校友。

不知道您是否还记得我，我是曾在大四修过您几门课的校友。

I'm not sure if you remember me, but I'm an alumnus who took a couple of your classes during my senior year.