I want a glass of milk.对a glass of milk 提问
问题描述：
I want a glass of milk.对a glass of milk 提问
答
初中题目？
应该是What do you want? 你需要什么
I want a glass of milk. 我需要一杯牛奶
楼主问这类题目最好写的详细点，另外楼上的how much milk do you want?是对a glass 题问，问的是多少，而不是需要要什么。
至于What would you want to 就是病句了，缺少了谓语，应该为what would you want to drink?你要喝什么。
答
这个是对你要一杯牛奶提问，而不是一杯提问，所以一楼的回答不对，应该是：
what would you like ？意思是：你想要什么？
希望能帮到你
答
How much milk do you want?
答
What would you want to?