Comparisons with as...as

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.

To Express similarity 

Use as...as with an adjective to indicate how two things are equal or the same. Use the adverb just for emphasis.n

Example

The new speakers are as good as the old ones.

Use the adverb almost un affirmative statements to indicate the two things are very similar but not exactly the same.

Example

The Zeta B es almost as fast as the Panasox.

To express difference

Use not as...as to indicate how two things are different. Use not quite when the difference is very small. Use not nearly to indicate that there's a big difference.

Example

Our new printer isn't as noisy as the old one.