Some, Something and Someone are used in affirmative sentences.
Any, Anything, Anyone are used in negative sentences.
- Can I have/get SOME ... ? Can you give me SOME ... ? (There's certainly SOME of it.)
- Do you have ANY ... ? Is there ANY ... ? (We're not certain whether there's ANY of it.)
Some and Any come along with nouns: some water, any idea, some people, any problem.
**Exception: Do you have any friends in town? Yes, I have SOME. I don't have ANY. (No need to repeat friends. It's obvious.)
Something and Anything come alone and represent things: I want to eat something (=some food). I didn't understand anything (=any word/idea).
Someone and Anyone come alone and represent people: Someone is knocking the door (=some person). I didn't know anyone at the party (=any person).
I don't know ...... about economics.
She doesn't have ... cash but I have .... .
I know .... who can give you ... help.
Do you have .... euro coins? Sorry, I don't have .... .
Can I get ... biscuits? Sure, take ... .
She said ... , but I didn't understand ... word.
It's a secret. Please don't say ... to ... !
Check the answers in the comment section.