the nember of,a great deal,a plenty of,a lot of,四者之间的区别

1.the number of 意思为“。。。的数量”，修饰名词作主语时谓语动词用单数
相似的a nmber of 则表示“许多”，谓语动词用复数。
2.a great deal of “大量的”，修饰不可数名词，谓语动词用单数
例：He has given us a great deal of help
A great deal of work has been done to improve the people"s living standard.
与a great deal of 用法相同的有a large amount of
如：He has spent a large amount of momey on his new house.
3.a plenty of 即可修饰可数名词，也可以修饰不可数名词.接可数名词时，谓语动词用复数。接不可数名词时，谓语动词用单数。
例：we have plenty of time.
there are plenty of eggs.
a lot of 的用法与a plenty of 的用法相似，都可接可数名词或不可数名词

the number of 后面要跟的可数名词的复数，谓语动词用单数，它指的是……的数字是多少
a great deal of后面要跟不可数名词，谓语动词用单数
plenty of 不能和a连用，它可以跟不可数名词，也可以跟可数名词的复数，谓语动词根据名词来变化。
a lot of相当于 lots of,用法和plenty of 是一样的

a number of与可数名词复数连用 the number of与可数名词的单数连用 a great deal of与不可数名词连用 a lot of与plenty of两者皆可使用