brainiac

Everyone says my friend is a brainiac because she always finishes exams in half the time.

用法提示：brainiac 是可数名词，表示才智超群的人，这里作表语。

You don't have to be a brainiac to use this app; the instructions are very clear.

用法提示：brainiac 作可数名词，指才智超群的人，这里接在不定式后作补足语。

When our team got stuck on the math problem, the brainiac next door came over and helped us.

用法提示：brainiac 是可数名词，意为才智超群的人，句中作主语。