Just being active, like when you run around at outside or play basketball at achool, is a type of exercise.
这是改错题， 答案是去掉了at, 为何呢？
Just being active, like when you run around at outside or play basketball at achool, is a type of exercise.
只不过维持活跃，譬如你在户外跑步或者在学校打篮球，都是一种训练。
outside 本事就是一个地址副词，副词前面不可以再加介词
around outside在外面
I started puttering around outside, not knowing what I was doing.
我开始在外面闲荡，不了解自己在干什么。
A bunch of kids were hanging around outside.
一群青年在外面到处游逛。
Why are you lurking around outside my house?
你在我房屋外面鬼鬼祟祟的，想做什么？（为介词）