A drop in the bucket
Angela: "I'm sorry I scratched your car."
Andy: "Don't worry about it. It's just a drop in the bucket. That car has more scratches on it than I can count."
安吉拉：真对不起，我把你的车给划了。
安 迪：别担心。这不过是沧海一粟，这辆车上的划痕我都数不过来了。
A drop in the bucket" is a something that is not important because it is very small.
中文意思：沧海一粟，九牛一毛。
A chip on the shoulder
Angela: "What's bothering that guy?"
Andy: "Nothing. He's just got a chip on the shoulder."
安吉拉：那个家伙碰到什么麻烦了？
安 迪：没什么。他只是有点自卑罢了。
To start a fight, men used to put chips of wood on their shoulder and challenge others to "try to knock it off".
中文意思：自卑感；喜欢向人挑衅。