an amount of,a number of,the amount of,the number of的意思与区别?

问题描述:

an amount of,a number of,the amount of,the number of的意思与区别?

an amount of / a number of 表示很多,前者修饰不可数名词,后者修饰可数名词
the amount of / the number of 表示某样东西的数量,前者修饰不可数名词,后者修饰可数名词