some / any / a lot of

We use 'some' in positive (affirmative) sentences with both countable nouns in the plural and uncountable nouns: I have some apples; There is some milk in the fridge. We also use 'some' in offers and requests because we expect the answer to be 'yes': Would you like some tea? Can I have some bread, please? We use 'any' in questions and negative sentences: Is there any juice? There isn't any sugar. A common mistake is using 'some' in ordinary questions — save 'some' for offers and requests only. 'A lot of' (or 'lots of' in informal English) means a large quantity and works with both countable and uncountable nouns in positive sentences, negatives, and questions: There are a lot of students in the class; She doesn't have a lot of time; Do you have a lot of homework? Both 'some' and 'any' can stand alone without a noun when the noun is understood from context: 'Do you have any biscuits?' — 'Yes, I have some.' For example: 'There are a lot of oranges on the table, but there isn't any orange juice in the fridge — would you like some water instead?'