Not "I have any books." — say "I have some books.". "I have" 这种普通句子是肯定句，所以用 some，不用 any。
试一试: She bought ___ apples at the market. (some / any) 答案: some — 这是个普通的肯定句（她确实买了），所以用 some：some apples. any 是给否定句和大多数问句用的（马上就会讲到）。
否定句或问句里用 any
当句子是否定的（don't、isn't），或者只是想问某样东西存不存在，通常就要换成 any。
I don't have any money.
There isn't any milk.
Do you have any questions?
Not "I don't have some money." — say "I don't have any money.". "Don't have" 让句子变成否定句，所以 some 要换成 any。
试一试: There isn't ___ coffee left. (any / some) 答案: any — "Isn't" 让这句变成否定句，所以要用 any：isn't any coffee. Some 是给普通肯定句用的。
试一试: Do you have ___ brothers or sisters? (any / some) 答案: any — 这是在问某样东西存不存在的问句，所以用 any：any brothers or sisters.（普通问句会把 some 换成 any。）
提供或请求时用 some
当你提供什么（Would you like...?）或者请求什么（Can I have...?）的时候，用 some。这类问句本来就期待对方回答yes，所以不是那种"到底有没有"的问句。
Would you like some tea?
Can I have some water, please?
Could you give me some help?
Not "Would you like any tea?" — say "Would you like some tea?". 你是在提供东西，也期待对方说yes，所以用 some，不用 any。
试一试: You are offering a guest a drink: Would you like ___ juice? (some / any) 答案: some — 你是在提供东西，不是单纯在问有没有，所以用 some：some juice. 热情的提供就算是问句也用 some。
试一试: Positive, or a no or question? We don't need ___ help, thanks. (any / some) 答案: any — "Don't need" 让句子变成否定句，所以用 any：don't need any help.（普通肯定句 → some；否定句或问句 → any。）
试一试: The word can change inside one talk. Sofia offers: "Would you like ___ tea?" Then she looks in the cupboard: "Oh no, there isn't ___ tea left!" (some … any / any … some / some … some) 答案: some … any — 第一句是在邀请，邀请要用 some：Would you like some tea? 接着 "isn't" 让第二句变成否定，所以换成 any：there isn't any tea。同一段对话、同一个词——由周围的句子决定。