So what do you think about the story of Yu Gong？l think it is a little bit silly. It doesn’t seem very possible to move a mountain. But what could Yu Gong do instead of moving the mountains？He could build a road.
这一段落里的为啥用could不用can呢?
这里表示 Yu Gong “能够”，是过去的事情，所以用could不用can。
