知道了，谢谢！

There is a long queue in front of the counter that sales sliced noodles already.

This sentence means "There has already been a long queue in front of the canteen window that serves sliced noodle soup, right after the class is over in the afternoon." That probably implies that the noodle soup is so delicious that everyone rushes to buy it right after the class, so a queue quickly appeared.

这是整个的句话：”中午刚下课，卖刀削面的窗口前就排起了长队”。

这句话前面是不是还有一句？比如说，一大早，卖刀削面的窗口前就排起了长队。这句话的意思是这家的刀削面很受欢迎，很多人排队去购买。