在什么情况下用differences,什么情况下用difference.两者有什么区别,

difference 可作可数或不可数名词.
意思是“不同之处”时为可数名词.
意思是“差异”时为不可数名词.
There are many differences between the two languages.
这两种语言有很多不同之处.
There was not really much difference in their points of view.
他们的观点没有多少真正的差别