“他在上课的时候居然趴在桌子上睡着了”求助这句话的英文翻译

How could he fell in sleep on desk in class!

He even dropped in front of the school when asleep on the table .
He in attends class time unexpectedly lay prone on the table is resting.
他在上课的时候居然趴在桌子上睡着了

He actually fell asleep on his desk during the class.

He actually fell asleep at his desk during the class

应该是用介词at
而不是on