It's a rotten apple, it's a ripe apple.

这是一个烂苹果，这是一个熟苹果。

So that's a rotten apple, a person who is kind of corrupt and has bad ideas, and is also influencing people around him or her in a negative way.

所以这是一个烂苹果，一个有点腐败、有坏主意的人， 也以消极的方式影响着他或她周围的人。