上学期，我们男生寝室和你们女生寝室有过一次联谊活动？碰巧你不在。
shàng semester ，wǒmen nánshēng qǐnshì hé nǐmen nǚshēng qǐnshì yǒuguò yīcì liányì huódòng ？pèngqiǎo nǐ bù zài 。
Last term, the boy's dormitory and the girl's dormitory had a get-together. It happened that you were not there.