When we want to compare two or more nouns, adjectives or adverbs we use the comparative and superlative forms. Grammatically the main difference is between comparing 2 items or comparing more than 2 items.
Comparing 2 Items
To compare two items, we use the comparative:
I am big, he is bigger.
She works carefully, he works more carefully.
We often use this form in this pattern:
{comparative} + {than}
He is taller than me.
We are more efficient than you.
See the main article, Comparatives for more on this.
Comparing More than 2 Items
To compare more than two items, we use the superlative:
Jupiter is the biggest planet in the solar system.
In the company, Sandra works the most carefully.
If the context is clear, we do not need to use a complete comparison. We can say:
This book is more difficult.
The rest of the sentence is implied:
This book is more difficult (than that book).
We often use the superlative with the present perfect simple like this:
{superlative} … {present perfect + ever}
It was the most boring film I have ever seen.
That was the most disgusting meal I have ever had to eat.
Forming the Comparative & Superlative
Small words add -er and -est to make the comparative and superlative. Large words use the and more and most
adjective – comparative – superlative
small – smaller – the smallest
extensive – more extensive – the most extensive
Note that the superlative often takes the with it.