替代词one与the one的用法区别

　　A fast train is one that goes fast. 快车是一种行驶快的火车。

　　The accident was similar to one that happened in 2008. 这个事故与发生在2008年的事故类似。

　　Open the drawer on the left, the one with a key in it. 打开左边的抽屉，上面有钥匙的那个。

　　Here are six rings. Pick out the one you like best. 这里有六枚戒指，选出你最喜欢的一枚。

　　I want very much to see these films, especially the one you mentioned. 我很想看这些电影，特别是你提到的那一部。

　　注：the one与that均可表特指，但前者只用于替代单数可数名词，而后者则可用于替代可数或不可数名词。