how long,how much,how many有啥区别?他们的回答有何不同?

how long, 多长
how long have you been in Shanghai.
你去上海呆了多久？
how much 多少（钱）（接不可数名词）
huw much is this?
这个多少钱？
how much money do you have?
你有多少钱？
how many 多少（接可数名词）
how many apples are there?
那有多少苹果？

均可表示“多少”how many 修饰可数名词的复数形式，而how much 修饰不可数---How long is the desk？这张桌子有多长？ ---1.2 meters. 1.2米

how long是提问时间的，“所长时间”如how long can I borrow this book?-Ten days.
how much是提问程度的或对不可数名词数量的提问。How much will it cost? -Ten hundred yuan.
how many是对可数名词的数量进行提问的，如how many apples are there?-Ten.

how long是问多长时间, how many是问多少,后加可数名词复数, how much是问多少钱,也可以问多少,后加不可数名词

how long 多久,一般回答时间段
如：How long have you been in this school?
I have been here for about two hours.
how much 多少,后跟不可数名词,回答用数量
如：How much water is there in the bottle?
There is little.
How much 还有 多少钱的意思
how many 多少,后跟可数名词复数,回答用数量
如：How many students are there in your class?
There are forty.