a great deal of和a great numberof的区别

a great number of 和a great deal of 在意思上相同,但用法不一样.。a great number of 后面只能跟可数名词的复数形式，而a great deal of 后面只能跟不可数名词。
例如：
A number of books are missing from the library. 图书馆的一些书不见了。
I spent a great deal of my time on this work. 我在这项工作上花了不少时间。

a great deal of +不可数名词，“许多；大量”
a great number of+可数名词的复数， “许多；大量”

　　a great deal of 后面只能跟抽象名词或物质名词，a great deal也可用作状语。
　　The race gave every one a great deal of pleasure.这次比赛给了大家许多乐趣。
　　There was a great deal of excitement just before it began.比赛开始前，人们非常激动。
　　A great number of houses have sprung up everywhere.
到处都新建了许多屋宇。
　　A great number of families lived in this village.
这个屯落里有许多人家。
　　a large number of 多数，大量,如：
　　His errors spawned a great number of economic loss.
　　他的错误造成了极大的经济损失。