嘿

嘿，你怎么把这件事给忘了？

hēi, nǐ zěn me bǎ zhè jiàn shì gěi wàng le?

Hey, why did you forget this?

嘿，张教授，真没想到在千里之外的国际学术研讨会签到处居然能与您不期而遇！

hēi, zhāng jiào shòu, zhēn méi xiǎng dào zài qiān lǐ zhī wài de guó jì xué shù yán tǎo huì qiān dào chù jū rán néng yǔ nín bù qī ér yù!

Hey, Professor Zhang, I never expected to meet you unexpectedly at the sign-in counter for an international academic seminar thousands of miles away!