Maybe I give you a lecture ahead of time, and I give you a bicycle for two weeks, then I come back after two weeks, and say, "Well, let's see. You're having trouble taking left turns.
我提前给你讲了骑自行车的内容， 之后我给了你一辆自行车和两周的时间， 两周后，我回来了， 说，“奥，你左转弯有点问题， 你不会紧急刹车，