With almost no exceptions, comparative adjectives are formed either by adding
-er or by using
more:
Jill is smart -> Jill is smarter than Penny.
Jill is intelligent -> Jill is more intelligent than Penny.
The same pattern occurs with the superlative forms
-est and
most (Note that if an adjective takes the
-er form, it will also take the
-est form, and likewise for
more and
most):
Jill is the smartest student.
Jill is the most intelligent student.
Non-native speakers of English often find it difficult to know when to use the
-er form and when to use the
more form. Unfortunately, there isn't a perfect rule for this, but you can still improve your chances of guessing right with a few simple tips.