A A bad egg

You can test eggs by putting them in water, a good egg will sink but a bad egg will rise to the surface.

你可以把鸡蛋放入水中来检验它们的好坏，好蛋会下沉，而坏蛋会浮到水面上来。

Restaurants can sometimes be breeding grounds for outbreaks if they crack many eggs into a single container when preparing them, which could allow one bad egg to contaminate a whole batch.

餐馆可能会滋生病菌并导致爆发，如果他们将许多鸡蛋打入其准备的一个容器中，若有一个坏鸡蛋就会污染整个。