肯定句特别是口语中，通常用a lot of和lots (of)而不是much (of)和many (of)，然而有以下例外
a) 正式或学术报告中，much (of)和many (of)更常用，同样常见的还有a large/considerable/substantial amount of（不可数名词）或a large/considerable/great/substantial number of （可数名词），例句如下：
Much debate has been heard about Thornton's new book.
There could be many explanations for this.
Much of her fiction describes women in unhappy marriages.
A large amount of the food was inedible. （或Much of...）
The book contains a large number of pictures, many in colour. （或...many...）
b) 正式书写中，much和many可以作介词用，例句如下：
There is no guarantee she will recover. Much depends on how well she responds to treatment.
Many (=many people) have argued that she is the finest poet of our generation.
Not once did I see a tiger in the jungle, although I heard many.
c) 通常用many而不是a lot of或lots of修饰时间单词例如days, minutes, months, weeks, years，数量+of+名词（例如thousands of voters, millions of pounds）前通常加many
We used to spend many hours driving to Melbourne and back.
He was the founder of a company now worth many millions of pounds.
many可以跟在the, my, its, his, her等和复数名词后面，例如
Among the many unknowns after the earthquake is the extent of damage to the foundations of buildings.
The gallery is exhibiting some of his many famous paintings of ships.
讲述重复发生的现象行为或一大群人、物时可以用many a+单数名词，例如：
Many a pupil at the school will be pleased that Latin is no longer compulsory.
强调数量很大的时候可以用a good/great many + 复数名词或a good/great deal of+单数名词或不可数名词例如：
She has a good/great many friends in New Zealand.
A good/great deal of the exhibition was devoted to her recent work.
too mnay+复数名词或too much+不可数名词前加far进一步强调程度，例如
Far too many students failed the end-of-year maths exam. （不是Much/Many too many...）
Far too much time is wasted filling in forms. （不是Much/Many too much time...）
通常是plenty of+不可数或复数名词而不是a lot of或lots of，但是要注意plenty of是足够，或者超过需求量的意思，所以需要根据语境判断是否适合使用，例如：
We took lots of/plenty of food and drink on our walk through the hills. （正确）
Nina doesn't look well. She's lost a lot of weight. （这里不能用plenty of）