1、many、a great/good many 、a great/large number of 、scores of、dozens of和 (quite) a few, 这类“许多”修饰作主语的名词时，只能修饰名词复数形式，谓语动词用复数。
There are a great/good many English books in our school library.
2、the number of + n （可数名词复数） 表示"....的数目”,用它做主语时，谓语用单数
The number of the students in our class is 55.
3、既可以修饰可数名词复数， 又可以修饰不可数名词a lot of 、lots of 、plenty of 、supplies of ，a great/quantity of 、great/large quantities of。
He has got a lot/lots of questions to ask.
4、只能修饰不可数名词的“许多” 有：much、a great / good deal of 和a large amount of ，这类“许多”修饰主语名词时候， 谓语用单数。
I don't know they gave us much help.
5、a great deal 做名词词组和副词词组，也表示“大量，许多”，还可以修饰比较级，表示程度。
At the end of the year there was a great deal to do.年底有很多事情做。
6、many a /an + 单数可数名词也表示许多，这个短语作主语时谓语用单数。
Many a girl in our class has learned to swim.
a (great/large)number of+(c)
a (great/large) amount of+(un),注意没修饰词用AN amount of
plenty of +c/u
a great deal of+un
many a（+可数单）谓语单!本回答被网友采纳