Adjectives are used to describe and give more information about a noun. They can have 3 different degrees:
1.- Positive adjectives
They are used to describe a noun, not to compare. They can be used in front of the noun or after a link verb.
2.- Comparative adjectives
They are used to compare two things. They show the superiority, inferiority, or equality of one term compared to another.
In the first two cases, they are usually followed by the word ‘than’. If the adjective has two syllables, you turn it into a comparative adjective adding –er; if it has three or more syllables, you add ‘more’ for superiority or ‘less‘ for inferiority before the adjective.
When showing equality, use as + adjective + as, without changing the adjective.
3.- Superlative adjectives
They are used to compare three or more things, or to describe extremes. If the adjective has two syllables, you turn it into a comparative adjective adding –est; if it has three or more syllables, you add ‘most’ before the adjective.