She is such a do-gooder, always trying to impress other people.

她倒是一个做好事的人，但常常是为了给人们留下深刻的印象。

He was supposed to be a brute, a villain -- not a nerdy do-gooder.

他想让大家认为自己是一位土霸，恶棍--而不是勤奋好学的书呆子。

Best is something different. When you're talking about a good country, you can be good, gooder and goodest.

最优秀是另一个意思。当你说一个国家是好国家，你可以是好的，更好的和最好的。