The old class is at the window. （注：根据上下文不同，这句话可能有多种理解方式。如果“老班”指的是班主任，可以翻译为 "The head teacher is at the window." 如果需要更具体的语境，请提供更多信息。）

A student was secretly playing with his mobile phone in class. Coincidentally, the head teacher was patrolling outside the classroom and noticed him playing with his phone while sitting by the window. Then, the teacher took out his phone and sent him a text message: "Why aren't you paying attention to the class?" The student, confused, replied: "Who are you?" The teacher sent another message: "Look outside the window." After taking a glance outside, he secretly replied: "Wait a sec! Shit! Our head teacher is outside!"