这个问题语言学家的观点也不尽一致。且不说国内的语法著作，就连国外的语法著作和词典也有分歧。如《牛津高阶学习词典英汉双解》第七版在 the 词条，只给出了一种词性，即definite article（定冠词）；而《朗文当代英语大词典》第4版在 the 词条，则给出了两种词性，即 (1) definite article & determiner（定冠词和限定词）；(2) adv（副词）。同时在副词词性下面给出了以下用法说明和例句：

1. used before two COMPARATIVE adjectives or adverbs to show that the degree of one event or situation is related to the degree of another one 〔用于两个形容词或副词的比较级之前，表示两件事或两种情况的相关性〕

The more he eats the fatter he gets. 他吃得越多就越胖。

'When do you want it?' 'The sooner the better.' “你什么时候想要？”“越快越好。”

2. used before an adjective or adverb to emphasize that something is bigger, better etc than all others, or as big, good etc as it is possible for it to be 〔用于形容词或副词前，强调是最大的、最好的等〕

He likes you the best. 他最喜欢你。

I had the worst headache last night. 我昨晚头痛得厉害极了。