Here are some comparative adjectives. They are, of course, describing words that compare things like these three apples:
or like these three fish:
We usually add 'er' for the comparative form and 'est' for the superlative form. BUT, of course not always! After all, this is English you are learning - the language with the greatest (superlative) number of exceptions to its rules.
While it is fine to say,
"this picture is bigger than that picture"
we may not say,
"this picture is beautifuler than that picture."
Nor may we say,
"this picture is the beautifulest one."
This may lead you to ask the very reasonable question, "Why not?" Well, it is because three-syllable words are the exceptions to the +er and +est rules. With three-syllable words we form the comparative and superlative forms by using the words "more" and "most."
"This picture is more beautiful than that picture."
"This picture is the most beautiful of all."
But, alas, there are yet other exceptions to the +er and +est rules. For instance if you are using a past participle such as, crooked, or broken, then you also use the words "more" and "most" to express the comparative and superlative forms.
"Our house was the one most damaged in the storm."
And lastly, there is the case of some predicate adjectives. These adjectives occur in the predicate part of a sentence (after a linking verb) but describe the subject. These are words like, afraid, mute, certain, alone, and silent. We might say,
"Of all our children, Irina was the most afraid of water."
There are a few exceptions to the exceptions, but I think the information here will serve you well. Study the charts and create some practice sentences. You will soon see your skills with comparative adjectives moving from good, to better to BEST!
Exceptions which use "more" and "most" and exceptions that are ~~ well, just exceptions: