{much many}意思上=lots of=a lot of= some+可数不可数名词 A number of+什么

a number of 意思：许多 用法：后跟可数名词作主语时要看作复数 例句：a number of pupils are having lunch.
扩展一下,这几个要区别!
the number of .的数目 后跟可数名词做主语时要看作单数 例句：the number of the players is 9.
numbers of 和 a large number of 修饰可数名词