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