【Emily Lin】評論
Mary : How was it that they discovered the entrance to the underground palace? = How did they discover the entrance to the underground palace? Mark: Totally by chance.
【97017017 9701】評論
Mary:他們是如何發現地下宮殿的入口?Mark:完全就是意外(偶然)it 代替 they discovered the entrance to the underground palace當虛主詞