Wah How to compare things with "As"

When you would like to compare two things when they have almost or exactly the same qualities. We use...

When two things have exactly the same qualities. We can use just before as. 
    I am (just) as tall as him. (I have the same height as him.)
    It's (just) as hot as the hell.
    You can speak English as well as me.

When two things have almost the same qualities. We can use almost before as. 
    That fish is (almost) as big as me. (I am bigger, but not much bigger.)
    He is (almost) as clever as Einstein.

In the negative sentence, we can use not as adjective/adverb as in the same way as the comparative form.
    This salad is not as good as Caesar salad. (Caesar salad is better.)
    He is not as rich as Warren Buffett.

Note : We cannot use just as...as... in negative sentences.

Idiom

as bad as all that
as bad as it seems,as bad as reported,as bad as it could be (Usually expressed in the negative.) 
    Stop crying. It cannot be as bad as all that.
    Cheer up! Nothing might be as bad as all that. 

as blind as a bat
Completely blind,Very bad eyesight, Not able to see well. 
    Without his glasses he is as blind as a bat.
    It is very foggy I am as blind as bat.

as easy as pie
Very simple,Very easy
    This Work is as easy as pie, I can finish it in 10 minutes.
    You'll find the examination is as easy as pie.