As ... as
[color=]from English Grammar Today[/color]
We use as + adjective/adverb + as to make comparisons when the things we are comparing are equal in some way:

The world's biggest bull is as big as a small elephant.

The weather this summer is as bad as last year. It hasn't stopped raining for weeks.

You have to unwrap it as carefully as you can. It's quite fragile.


Comparison: adjectives (bigger, biggest, more interesting)


Not as ... as
We use not as ... as to make comparisons between things which aren't equal:

It's not as heavy as I thought it would be, actually.

Rory hasn't grown as tall as Tommy yet.

She's not singing as loudly as she can.

They didn't play as well as they usually do.

We can modify not as ... as by using not quite as or not nearly as:

The second race was not quite as easy as the first one. (The second race was easy but the first one was easier.)

These new shoes are not nearly as comfortable as my old ones. (My old shoes are a lot more comfortable than these new shoes.)

We can also use not so ... as. Not so ... as is less common than not as ... as:

The cycling was good but not so hard as the cross country skiing we did.


As ... as + possibility
We often use expressions of possibility or ability after as ... as:

Can you come as soon as possible?

Go to as many places as you can.

We got here as fast as we could.


As much as, as many as
When we want to make comparisons referring to quantity, we use as much as with uncountable nouns and as many as with plural nouns:

Greg makes as much money as Mick but not as much as Neil.

They try to give them as much freedom as they can.

There weren't as many people there as I expected.

We can use as much as and as many as before a number to refer to a large number of something:

Scientists have discovered a planet which weighs as much as 2,500 times the weight of Earth.

There were as many as 50 people crowded into the tiny room.