① a great many和a good many同义，意为“许多”，是many的强调形式，只能作定语，后跟复数可数名词。
I have been to the city a great many times. 我曾多次到过那个城市。
He has worked here for a good many years. 他在这里工作已经很多年了。
② a number of意为“许多，一些”，后跟复数可数名词。表示强调时，可以说a great/large/good number of或quite a number of。number还可用small，big修饰。a number of多用于肯定句，在疑问句或否定句中要用many。
Quite a number of students are on the sports ground. 操场上有许多学生。（不可说a quite number of）
A great/large/good number of people have come to the party. 许多人都来参加这个晚会。
③ 下面几个短语后可以跟不可数名词或复数可数名词：
a large quantity of a small quantity of
a great quantity of plerfautu
plenty of money/books 许多钱/书
a large quantity of water/trees 大量的水/树
④ a great/good deal of一般修饰不可数名词，但偶尔也修饰可数名词。
There is a great deal of oxygen in the air. 空气中有大量氧气。
They have spent a great deal of money on the project. 他们在这项工程上花费了大量资金。
⑤ a great amount of，a large amount of和a small amount of后跟不可数名词，不可跟可数名词。
He spent a great amount of time reading these books. 他读这些书花了很多时间。
He sent her a small amount of money. 他给她寄了一小笔钱。