为什么一份报纸不能用a piece of而要用a copy of?

为什么一份报纸不能用a piece of而要用a copy of? 一份报纸 是a piece of newspaper还是a copy of newspaper? a piece of 为什么 several pieces of wood/a piece of wood为什么只能用several pieces of wood,而不用a piece of wood呢? 两份报纸和两张报纸英文怎么说?我知道newspaper是可数明词我们说一份报纸 a newspaper 两张报纸能不能用 two newspaper 为什么还有两张报纸怎么说谢谢还有个问题读报纸的英文是read newspaper 还是re 一般说a slice of tomato但是不知道能不能用a piece of tomato呢? I did a lot of Christmas shopping.a lot of为什么不可以换成 a piece of catch和hold的区别?The Crow held a piece of cheese.为什么不填cought a piece of summer.a piece of a piece of chalk改成a chalk不行吗?为什么要加piece of啊?chalk好像是可数名词啊,粉笔不是论根的吗? 是a piece of clothing正确还是a piece of clothes正确呢,为什么? a piece of work a blank piece of take a piece of A piece of a piece of a piece of cake a piece of paper