a great many 很多的,非常多的.只能用来修饰可数名词 .
还有一些修饰可数名词的词或词组如：a good many,
a number of ,many ,few
修饰不可数名词的有：a great deal of,
a large amount of ,much ,little
即修饰可数又修饰不可数的有：plenty of,some,
any ,a lot of ,lots of ,a mass of,
masses of ,a large quantity of ,
quantities of