With bright beady eyes, they glanced shyly at each other, sniggering a little, sniffing and applying coat-sleeves a good deal.

他们睁着明亮的小圆眼睛，害羞地互相瞥了一眼，窃笑了一下，嗅了嗅，又把外套袖子擦了好多遍。

What are you sniggering at?

你偷偷笑什么呢？

Suddenly, three schoolkids sitting near me started sniggering.

突然，坐在我身边的3个学童偷偷地笑了起来。