Adjectives
Adjectives are used to describe or give information about things, ideas and people: nouns or pronouns.
Adjectives can have degrees of comparison. The three different forms of comparison are the positive, the comparative and the superlative.
 
The positive is the form of the adjective that describes one noun.
The comparative form of the adjective compares two nouns. The adjective in comparative degree is normally followed by than.
The superlative form of the adjective compares more than two nouns. We use the  before the superlative degree of an adjective. An adjective in the superlative degree is usually followed by of  or in.
In English, some comparisons are regular, that is:
  
a. The comparative degree of  single-syllable  adjectives is formed by adding -er ending, and the superlative degree by adding -est  ending to the positive form of the adjective.
b. The comparative degree of multi-syllable  adjectives is formed by adding the word more, and the superlative degree is formed by adding the word most  to the positive form of the adjective.
Օրինակ
I am rich. My smartphone is expensive. (Positive Degree)
Nare is richer than me. Her smartphone is more expensive than mine. (Comparative Degree)
Narek is the richest of all. His smartphone is the most expensive one in our class. (Superlative Degree)
Some comparisons are irregular, so you have to memorize them (see the table below).
 
Irregular Comparisons
Positive
Comparative
Superlative
good
better
best
bad
worse
worst
little
less
least
many
much
more
most
far
farther
furthur
farthest
furthest
old
older
elder
oldest
eldest
 
The as + adjective/adverb + as construction is used to express similarity or equality in its positive form.
It is also called a simile [’simili] - a way of describing something by comparing it to something else, often using the word like or as.
Օրինակ
He is as brave as a lion.
Your house is as large as mine.
In its negative form it is used to express difference.
Օրինակ
Your house is not as large as mine.
We can also replace the first as with so.  
Your house is not so large as mine.
This is more common in the negative and it is also more common in American English than in British English.
 
Ուշադրություն
Watch out for the spelling rules to help you make comparisons in English.
\(1\). For two-syllable adjectives ending in -y make comparisons by deleting the final -y and adding  -ier  and -ies (easy - easier - easiest)
\(2\). For one-syllable adjectives ending in a vowel + a consonant make comparisons by doubling the final consonats (big - bigger - biggest)
\(3\). For one-syllable adjectives ending in -e make comparisons by adding -r and -st (fine - finer -  finest
\(4\). For two-syllable adjectives ending in -er make comparisons by adding -er and -est (clever - cleverer - cleverest)
\(5\). For two-syllable adjectives ending in -le make comparisons by adding -r and -st  (simple - simpler - simplest
\(6\). For two-syllable adjectives ending in -ow make comparisons by adding -er and -est (narrow - narrower - narrowest)
\(7\). For two-syllable adjectives such as quiet, clever, narrow, and simple make comparisons by using both ways:  adding -er and -est (clever - cleverer - cleverest) and the words more and most (clever - more clever - most clever).