1.little 几乎没有
a little 有一点
There is little water in the botter.瓶子里几乎没有水了.
THere is a little water in the botter.瓶子里还有一点水.
都是修饰不可数名词,而且a little还可以表示抽象的少,如：
I like him a little.有一点喜欢他.
2.lot :a lot （很对,修饰抽象的多,如I like him a lot（相当于I like hime very much)
a lot of=lots of 既可以修饰可数名词又可以修饰不可数名词.
3.less 是little的比较急,较少的,也修饰不可数名词,并可以修饰比较级.
There is less tea in the cup now.现在杯子里的茶少了些.
He is less fatter than Jim.他没有Jim胖.