latter和former，在通常情况下是形容词，当跟the连用时，直接视为代词即可。《柯林斯》解释如下：

PRON When two people, things, or groups have just been mentioned, you can refer to the second of them as the latter. 后者
He tracked down his cousin and uncle. The latter was sick. 他追踪找到了他的堂兄和叔叔。后者病了。
PRON When two people, things, or groups have just been mentioned, you can refer to the first of them as the former. 前者
They grappled with the problem of connecting the electricity and water supplies. The former proved simple compared with the latter. 他们设法解决供电和供水的连接问题。前者与后者相比证明很简单。