首先谈谈how much 的用法.它有三个用法：
第一：对不可数名词的数量进行提问,how much + 不可数名词.
例如：I have some milk. 对some 提问,就用how much, How nuch milk do you have?
再如：There is much water in the bottle. 对much 提问,就用how much, How much milk is there in the bottle?
第二：对物品的价格进行提问.
例如：This computer is 4000 yuan. 对4000 yuan 提问,就用how much, How much is this computer?
再如：These flowers are 40 yuan. 对40 yuan 提问,就用how much, How much are these flowers?
第三：对了解程度进行提问.
例如：How much do you know about your school?
再如：How much does she know about the restaurant?
在理解了how much 的三种用法之后,就可以清楚知道how much is/are 的用法了.是对物品价格的提问.