All refers to three or more items. It is used mostly before plural and uncountable nouns.
- All children need love.
- I love all music.
- All the invitees turned up.
When all is followed by a plural noun, the verb is normally plural. After an uncountable noun, we use a singular verb.
- All cheese contains fat.
- All the lights were out.
All + noun is not normally used as the subject of a negative verb. We more often use the structure not all + noun + affirmative verb.
- Not all birds can sing. (NOT All birds cannot sing.)
All and All of
Before a noun with no determiner (possessives, articles and demonstratives) we use all.
- All children need love.
- All cheese contains fat.
- All lights were out.
Before a noun with a determiner (the, my, this etc.), all and all of are both possible.
- All the lights were out.
- All of the lights were out.
- I have invited all my friends to my birthday party.
- I have invited all of my friends to my birthday party.
Before a personal pronoun (us, them etc.) we use all of + object form.
- All of us love music. (NOT All us love music)
- I have invited all of them. (NOT I have invited all them.)
All with nouns and pronouns
All can modify nouns and pronouns. We normally place it before the noun/pronoun.
- I have invited all (of) my friends.
- All of us love music.
- I love all of you.
- All of us are going to the movies.
We can put all after pronouns used as objects.
- I love you all. (= I love all of you.)
- Give my love to them all. (= Give my love to all of them.)
- I have made you all something to eat. (= I have made all of you something to eat.)
Note that all cannot be put after pronouns used as subject complements.
- Is that all of them? (NOT Is that them all?)