Comparatives: CURIOUSER vs. MORE CURIOUS

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.