be good at 的意思是擅长做某事，后面加名词或动名词，也可以加从句。
例句
You need manual dexterity to be good at video games.
玩好电子游戏手要灵巧。
We must be good at learning.
我们必须善于学习。
I used to be good at many things.
过去我擅长很多事。
What helps you to be good at sport?
是什么让你擅长运动？
I just want to be good at something.
我只是想有一项专长。
