Collins Cobuild English Grammar (189 page)

dirty

clever

easy

funny

happy

heavy

lovely

lucky

pretty

quiet

silly

simple

steady

tiny

R24
    Some other two-syllable adjectives usually have comparatives and superlatives formed with
more
and
most
.

careful		more careful		the most careful
famous		more famous		the most famous

Here is a list of common adjectives whose comparative and superlative forms are usually formed with
more
and
most
:

careful

common

famous

handsome

likely

mature

obscure

pleasant

polite

sudden

R25
    Many two-syllable adjectives can have comparatives and superlatives with either the endings
er
and
est
, or
more
and
most
. In many cases, the
er
and
est
forms are more commonly found directly before the noun (in attributive position), and the
more
and
most
forms more commonly follow a linking verb such as
be
or
become
(in predicative position). For more information about
attributive
and
predicative
adjectives
, see paragraphs
2.42
to
2.52
.

…major hurricanes such as Katrina, the
costliest
disaster in U.S. history.
Energy is becoming
more costly
and supplies are drying up.

Less space seemed to make for a
friendlier
neighborhood feeling.
We are encouraging employers to be 
more friendly
 to the local environment.

Here is a list of common adjectives that can have either type of comparative and superlative:

angry

costly

cruel

friendly

gentle

narrow

remote

risky

shallow

stupid

subtle

R26
    Adjectives that have three or more syllables usually have comparatives and superlatives with
more
and
most
.

dangerous		more dangerous		the most dangerous
ridiculous		more ridiculous		the most ridiculous

However, some three-syllable adjectives are formed by adding
un
to the beginning of other adjectives. For example,
unhappy
is related to
happy
and
unlucky
to
lucky
. These three-syllable adjectives have comparatives and superlatives formed either by adding
er
and
est
or by using
more
and
most
.

He felt crosser and
unhappier
than ever.

R27
    When you add
er
or
est
to an adjective, you sometimes need to make another change to the end of the adjective as well.

If a one-syllable adjective ends in a single vowel letter followed by a single consonant letter, you double the consonant letter when adding
er
or
est
.

big		bigger		the biggest
hot		hotter		the hottest