Though margarine was introduced as a supposedly healthful

[ivy]

And noun phrase is a phrase based on noun optionally accompanied by modifier such as adjective, isn't it?

So, 'healthful alternative' is a noun phrase.

[tim]

I would argue that a much simpler interpretation is to ignore this idea of a "noun phrase" entirely and just think of this as an adverb modifying an adjective modifying a noun. Can you provide an example of a "noun phrase" that cannot be interpreted more simply in this way? I’m just not convinced there is any justification for the concept of a "noun phrase" the way you seem to be describing it..

[SachinM450]

The second "as" is never optional when we are comparing adjectives. You cannot say "as X" by itself or "as X than Y"; you must instead say "as X as Y"..

Dear Expert,

The following is the correct answer to an official question. Could you please explain why the "AS MANY" is correct in this case without the second 'AS' ?

When drive-ins were at the height of their popularity in the late 1950s, some 4,000 existed in the United States, but today there are fewer than one-quarter AS MANY.

Appreciate if you could tell me how to identify when this form is acceptable and when it is not.

Thanks in advance!
Mathew

[Sage Pearce-Higgins]

I can see how Tim's post above could be confusing. He's right to show that the construction is 'as big as'. However, in the example that you show there's something else going on as well. Perhaps it feels like the sentence could continue, that part of it has been left out. Pause and consider what extra words might be missing.

The extended sentence could read: '...today there are fewer than one-quarter as many drive-ins as there were in the late 1950s.' Leaving out these words is pretty logical: we can understand the meaning of the sentence perfectly well without them. This is an example of what's called, in linguistics, ellipsis. It's something that's very common in English, particularly in sentences that make comparisons. Here's an article about it, with some good examples and way more detail than you need to know for GMAT.

In short answer to your question, we can use 'as many' at the end of a sentence or clause if the sentence or clause could continue with 'as...' to complete the logical meaning.