ONE OF MY FRIEND or FRIENDS

Hi Buddies!
Today I'm posting one of the most common grammatical mistakes that many learners of English make.

Quite often, I've heard and read many people use such sentences as 'Sam is one of my best friend.' , 'India is one of most populated country', 'Maths is one of her favourite subject' etc.

Although these sentences look okay at first sight, they are ungrammatical. As a rule ONE OF must be followed by a PLURAL NOUN. e.g. One of the boys, one of my brothers, one of the problems etc.

Therefore, the wrong sentences in the introductory paragraphs must be rewritten as: (Carefully see the plural subjects after 'one of')

'Sam is one of my best friends.' , India is one of most populated countries', 'Maths is one of her favourite subjects' etc.

The explanation:
In sentence 1, the speaker means to say that they have many best friends, and Sam is one of them.

In sentence 2, the speaker means to say that there are many most populated countries, and India is one of them.

In sentence 3, the speaker means to say that she has many favourite subjects, and Maths is one of them.

                                                                                                                    
Jacob (Nova English Campus)