Positive adjectives and adverbs can be used for comparing. Several different grammatical structures are possible.

As … as …

This structure is used to say that people, things, actions or events are equal in a particular way.

• A car is as fast as a bus.
• Alice is as beautiful as Mary.
• Tom is as tall as Harry.

If we want to say that people, things etc are unequal in a particular way, we can use not so … as … or not as … as …

• Tom is not as/so tall as Harry.
• A car is not as/so fast as a train.
• Alice is not as/so beautiful as Susie.

No other as … as …

This structure can be used to compare one person or thing with the whole group that she/he/it belongs to.

• No other girl is as intelligent as Alice.
• No other metal is as useful as iron.
• No other river is as long as the Niles.

As much/many … as …/as few/little … as…

This structure is used to make a comparison of quantity.

• I earn as much money as you.
• Alice has as many children as Mary.
• Tom earns as much as Harry.
• We have as many cars as them.
• They have as few visitors as we have.
• They have as little money as we have.

In an informal style, we use object pronouns (us, them, him etc.) after as. In a more formal style, subject pronouns are used usually with verbs.

• I earn as much money as he does.
• We have as many children as they have.

Not as much/many … as …

This structure can be used to say that quantities are not equal in a particular way.

• He does not earn as much as I do.
• Harry does not eat as much food as Tom does.
• We do not have as many visitors as them.