一、a great many 与 a great many of 的用法区别
1.a great many 与 a great many of 的用法区别，可以简化为 many 与 many of 的用法区别。
many既是限定词，用于修饰名词，也是不定代词，代替名词。在many farmers中，many是限定词;在many of短语中many是代词。通常情况下代词后接of...时，of后应该用特指的名词或代词。
例如 some students, some of the students;either side 与 either of the sides;much money 与 much of the money，以及 many soldiers 与 many of their soldiers 等。(当然，也有少量代词用法特殊的，比如 both (of) his daughters 中的 of 可有可无，这与 both 这个限定词的定位有关，在此不拟多谈。)
2.因为many of修饰名词时，是代词，而many修饰名词时是限定词，这样也造成了一些用法区别。可以说many of his friends,但不说many his friends,因为many是后位限定词，his是中位限定词，his须置于many之前。所以须将词序改为his many friends才合适。
二、修饰可数名词和修饰不可数名词的短语
修饰可数名词
修饰可数名词的有a good / great many, a large / great number of, scores of等，谓语动词用复数形式。
如：A great / good many words and expressions have come into the language from American English.
这门语言吸收了美国英语中的许多单词和短语。
There were scores of boxes, all waiting to be checked and loaded. 大批的箱子等着检验后装运。
修饰不可数名词
修饰不可数名词的有a large amount of等，谓语动词用单数形式。
如：He has spent a large amount of money on his new house.
他在新房子上花费了许多钱。
既能修饰可数名词，又能修饰不可数名词
既能修饰可数名词，又能修饰不可数名词的有：a lot of, lots of, plenty of等，谓语动词根据被修饰的名词是可数还是不可数来决定单复数形式。
如：There are a lot of / lots of people in that room.
那个房间里有许多人。
There’s a lot of / lots of rice in the bag.
那只口袋里有许多大米。
