few days ago I asked already about "a lot of". For better understanding I have one question again.
Can I say, that I have to use "a lot of" in every positve sentence, and much / many in every negative sentence and every question?
Please let me know when I'm wrong.
You can use "much" and "many" in positive sentences as well. It's just not done with any great frequency. It could sound "not quite right" depending on the sentence.
If "much" and "many" are used in a positive sentence, they are usually modified. Otherwise, you can stick with "a lot" just to be safe. However, "a lot of" can sound informal. I would say "much" sounds more formal when not modified.
We have so much to do. - We have much to do. There is much to do.
We have many things to do.
There are so many ________ .
You can use all three in a question. I think, maybe, "a lot of" would be more common. It also depends on whether the noun is uncountable or countable.
Do you have a lot of books?
Do you have many books?
Do you have much books? - Incorrect
Do you have much paper? - grammatical but unusual
Why do you have so much paper? - sounds better and is more usual when modified