The document discusses double comparatives, which compare two subjects using comparative forms of adjectives or adverbs. Double comparatives follow the pattern "the more/less X, the more/less Y" and are used to emphasize the relationship between two things. They show that as one element increases or decreases, the other element increases or decreases as well. Examples are given such as "the more you study, the more you learn" and "the faster the car is, the more dangerous it is to drive." Double comparatives are often shortened in spoken English, like "the more the merrier" and "the richer the better."