Here are the correct answers for each question:

16. I drank _____ glasses of milk but Lan didn’t drink _____.
**C. many/some**
- "Many" is used for countable nouns (glasses), and "some" is suitable for unspecified quantity when referring to countable nouns like glasses.

17. I haven’t got _____ money but I have _____ friends.
**D. much/many**
- "Much" is used with uncountable nouns (money), and "many" is used with countable nouns (friends).

18. Would you like _______ milk in your coffee?
**B. some**
- "Some" is typically used in affirmative sentences or offers/questions when a positive response is expected, which fits the context here.

So the final answers are:
16: C
17: D
18: B