Both are grammatically correct, depending on how you prefer your sentence to read. Most two syllable adjectives form two forms of the comparative and superlative. "Narrower" is the germanic-rooted comparative form of the adjective "narrow," while "more narrow" is the French-influenced version. "Narrowest" and "most narrow" are both acceptable superlatives.
A few other words that are correct both ways are handsome, clever, and simpler. Some say that "commoner" is an acceptable comparative adjective, but "more common" has become much more, well, common. Prefered forms (like much of English) makes a slow and steady tectonic shift as certain usages fall out of practice.
The second one is more correct.
adjective adjective: narrow; comparative adjective: narrower; superlative adjective: narrowestof small width. "he made his way down the narrow road"limited in extent, amount, or scope; restricted."his ability to get good results within narrow constraints of money and manpower"
Yes. The form who is the nominative, as opposed to whom.
It may be grammatically correct, but it is a logical absurdity. more/fewer is about counting more/less is about amount … so… no, it is not correct.
yes it is a real word. It is also correct grammatically and more stupid is not correct.
I am, you are, he/she/it is, we are, they are.
The phrase "how don't I" is not grammatically correct. A more correct way to phrase it would be "why don't I."
No.
No, "most friendly" is not grammatically correct. The correct form would be "friendliest" when comparing three or more things.
Yes
The second one is more correct.
Yes, the phrase 'what they're doing' is grammatically correct. For example: What they're doing is wrong.
Yes, "is much more easily" is grammatically correct because it follows the correct order of adverbs (much, more, easily) when comparing multiple items or degrees in a sentence.
No, it is not. The "question word," why, should be at the beginning of the sentence. Why was she promoted?
No. Us is the objective case, not the nominative case (we). It should be: We teens need more sleep. Or: We, as teens, need more sleep than others.
Both "you and he" and "he and you" are grammatically correct, but "you and he" is more commonly used in English.
Both are grammatically correct, but "do not feel" is better usage than "are not feeling."