as much (...) as or (...) as much as

Question

I know that 'as much/many as' act like adverb to show how much thing is compare to another.

In my English book (English grammar in use by Raymond Murphy, Cambridge) there are some exercises to write a new sentence with the same meaning.

I'm not sure how to put 'as much as' in my sentence when thing we explain is a noun phase.

The first one

There are fewer students in this class than in the other one

The book's answer is " There aren't 'as many students in this clas as' in the other room"

The second one

You known a bit about cars, but I know more

The book's answer is "You don't known 'as much about cars as' I do"

I feel confused when I have to seperate as much ... as Therefore I wonder could I put them as a group and speak like these

You don't know about cars 'as much as' I do.

There aren't students 'as many as' the other one.

Are they grammatically correct and sound naturally?

Answer 1

No

Neither of your uses are fully correct.

You don't know about cars as much as I do.

This would probably be correctly understood, but it is awkward and not idiomatic. What is being compared here is one person's knowledge of cars to another person's knowledge. The standards way to do that would be:

You don't know as much about cars as I do

To generalize this:

You don't as much as I do.

The term "as much" is placed after the first thing to be compared, and before the verb. The second "as" is placed after the object of the verb and before the second thing to be compared.

Note that "as much" by default shows a comparison of equals.

Joe brought as much as Jane.

to show that the first thing is smaller, we use "not as much".

The price was not as much as he has thought it would be.

To indicate that one thing was more than another using "as much" we negate the associated verb:

Joe didn't bring as much as Jane.

which means that Jane brought more than Joe.

These negated forms are very common when using "as much" but can confuse those new to this aspect of English. It is simply how "as much" is used.