One rotten apple spoils the whole lot.

一只烂苹果，弄坏全筐；害群之马。

This is not a rotten apple.

这可不是一颗烂苹果喔！

One rotten apple spoils the barrel.

一个烂苹果毁坏一筐苹果。

Ants swarmed all over the rotten apple.

烂苹果上爬满了蚂蚁。

The rotten apple injures its neighBors.

腐烂的苹果伤及邻果。