a great number of与a good many of的区别

第2个是a great many of
只能修饰可数名词的：a large/ great/ good number of,a good/ great many,dozens of,scores of,quite a few
只能修饰不可数名词的：a great deal of,a large amount of,quite a little,a large sum of
既可修饰可数也可修饰不可数名词的：plenty of,a lot of,lots of,a large quantity of,a good supply of

这两个没有区别 都是修饰可是名词的