Many/Much & A lot of are used as determiners. These words mean numerous or a large number of people or things.
Many is used with plural countable nouns, e.g. houses, shirts, people, children, etc. In everyday English, generally speaking, many is used in negative and interrogative sentences.
1. I’ve just moved to this town. I don’t know many people yet.
2. I feel a bit bored around here because I don’t have many things to do.
3. How many sentences do we have to make up?
4. So, have you got many friends yet?
Much is used with uncountable nouns, e.g. water, salt, sugar, coffee, etc. Like many, much is used in negative and interrogative sentences.
1. Sorry, there is not much money left in my wallet.
2. I don’t need much sugar for my coffee. I just need a little.
3. How much water do we actually use everyday for washing all this stuff?
4. Does this new bike consume much fuel?
Although the general rule says that many and much are used in negative and interrogative sentences, these words are also commonly used in positive sentences with “too, as, and so“. In other positive sentences, we prefer to use a lot of.
1. There are too many people in here that I feel uncomfortable.
2. My brother is popular. He has so many friends.
3. I have 2 bikes. John has 2 bikes, too. John has as many bikes as I do.
Many is also used in positive sentences, especially in formal text, like in newspaper, for example.
A lot of
A lot of has the same meaning as many and much. However, a lot of is used with both countable and uncountable nouns, and is used in positive sentences only.
1. She has a lot of money to spend in Bali.
2. Sorry, I got to go. I have a lot of things to do.