All

 What is all? 

All as a determiner or indefinite pronoun is a quantity word. It contrasts with some. It has similarities with every and both.

Positions of all

All can appear in many different positions in a sentence.

Position 1: all + of + noun phrase or pronoun

All of can be followed by :
1. a singular countable noun, for example, all of the audience
2. a plural countable noun, for example, all of the students
3. an uncountable noun, for example, all of the oil
4. a personal pronoun, for example, all of them, all of it

Other determiners can replace the, for example, all of our friends; all of that soup.

Note: With a singular countable noun, all (of) is not common. We prefer the whole.

Position 2: all + noun phrase

We can omit of from Position 1 (1-3). For example:
1. singular countable noun, for example, all the book, all this tree
2. plural countalbe noun, for example, all the books, all our friends
3. uncountable noun, for example, all the oil, all that soup

But we can't omit of before a personal pronoun: all them. Instead, we can place the pronoun before all: them all. [See position 3 below]

Note: The of must be omitted if the noun has no determiner.
Instead of: All of flowers are beautiful.
we must sy: All flowers are beautiful.

Position 3: personal pronoun + all

We place all after a personal pronoun whether the pronoun is subject or object. For example:
1. They all enjoyed the music.
2. I whis you all a happy New Year.

Position 4: noun phrase or pronoun + ... all

When the noun phrase or pronoun is a subject, we can often separate all, and place it after BE of the auxiliary verb.
1. You are all welcome.
2. The students are all playing in the class.
3. This oil will all have been used.

Position 5: all as a pronoun

As a pronoun, all can stand on its own. The of-phrase is omitted if its meaning is clear. For example: "Would you like to buy anything else?" "No, thank you. That's all." (= "That's all that I want")

Position 6: all as an adverb

All is an adverb of degree in the following examples.
1. Sam lives all alone. (= "completely")
2. Microsoft sells its products all over the world. (= "everywhere")

Let's see some idioms with all below:
1. all but = "almost"
2. all day
3. all over
4. all right: an adverb meaning "okay"
5. all through
6. (not) at all

I hope this article helps. If you have any question, please leave a comment below.