1. 兩者都表示“許多”，但 many 修飾或代替可數(shù)名詞(復(fù)數(shù))，與 few(少數(shù))相對;而 much 用來修飾或代替不可數(shù)名詞(單數(shù))，與little(少量)相對。如：
Did you see many people there? 你在那兒看見許多人了嗎?
Many poets have died young. 許多詩人很年輕就死了。
Do you have much money left? 你剩的錢多嗎?
He doesn't spend much time preparing his lessons. 他備課不花太多時間。
2. 關(guān)于many of 和 much of：
(1) 其后接名詞時，該名詞通常應(yīng)是特指的(比如有the, these, those, my, our, Tom's等修飾)。如：
Many of the farmers grow rice. 很多農(nóng)民種稻子。
Many of his ideas were amusing to her. 他的許多想法使她感到有趣。
He spends much of his time outdoors. 他很多時間都在戶外度過。
Much of the land was flooded. 大片土地被水淹沒。
(2) 如果名詞沒有表特指的限定詞，通常就不用of。如：
她沒有吃多少早餐。Many和Much的用法區(qū)別
誤：She didn't eat much of breakfast.
正：She didn't eat much breakfast.
大玻璃杯剩下的不多了。
誤：There aren't many of large glasses left.
正：There aren't many large glasses left.
(3) 如果用了介詞of又沒有特指限定詞，通常是不可以的。如：
誤：Many of students have read it.
正：Many of the students have read it. 許多學(xué)生讀過它。
誤：Much of time was wasted.
正：Much of the time was wasted. 大部分時間都浪費了。
(4) 在少數(shù)情況下，much of之后不跟限定詞也可以用，這主要見后接人名和地名的情形。如：
Not much of Denmark is hilly. 丹麥山地不多。
I've seen too much of Howard recently. 最近我見霍華德見得太多了。
(5) 在人稱代詞前總是用many of或much of，其中的of不能沒有。如：
I didn't eat much of it. 這個我沒吃多少。
Many of us were too tired to go further. 我們很多人都累得不能再往前走了。
(6) much of有時可用于一個還有不定冠詞的名詞前。如：
You can't see much of a country in a week. 一周之內(nèi)看一個國家看不了多少地方。
How much of a job would it be to rebuild the garage? 重建這個車庫工作量會是多少?
not much of a 有時可用于名詞前表示某人對某物或某人評價不高。如：
Then he's not much of a partner. 那時他不是什么了不起的合伙人。
That might not seem like much of an accomplishment. 那似乎算不上什么成就。
3. 兩者都可與 more 連用，其區(qū)別仍然是 many more之后接復(fù)數(shù)名詞，much more 之后接不可數(shù)名詞。如：
There have been many more burglaries this year. 今年盜竊案比過去多好些。
His car cost much more money than mine. 他的小汽車所花的錢比我的多得多。
有時其后的名詞可承前省略。如：
Many people support the government, but many more are against it. 許多人支持政府，但更多得多的人反對它。
另外，其后修飾的不是名詞，而是形容詞或副詞，則用much more，不用many more。如：
You must work much more carefully. 你應(yīng)工作得更加細心。
Politics is much more difficult than physics. 政治學(xué)比物理學(xué)難。
4. 注意“many a+單數(shù)可數(shù)名詞”的用法：形式上為單數(shù)，但意義上為復(fù)數(shù)(意為“許多”)，若用作主語，其謂語通常與形式一致而不與意義一致(即謂語用單數(shù))。如：
I have told him many a time to be polite. 我多次告訴他要有禮貌。
Many a young man has tried and failed. 很多年輕人都試過，而且失敗了。
注意，“many a+單數(shù)名詞”是一個十分正式的結(jié)構(gòu)，在口語或非正式文體中一般都用 “many+復(fù)數(shù)名詞”代之。
5. 與a great [good] number of, a great [good] amount of等表達不同，a great [good] many后接名詞時，不用介詞of。如：
I've known her for a great many years. 我認識她好多年了。
A great many people were at the meeting. 很多人參加了會。
但是，當其后接的是人稱代詞或帶有限定詞的名詞時，則要有of。如：
A good many of them have cars. 他們中的許多人有汽車。
A great many of the trees were destroyed in the storm. 這次暴風(fēng)雨毀了許多樹。
