主谓一致中,对于A and B是否为一个整体到底该如何区分?求详解!

and 连接的两个成对的名词,如fork and knife,bread and butter；soda and water； coffee and water；aim and end；salt and water等,虽有and 连接,但被看成不可分割的整体,仍表示单一的概念,谓语动词常用第三人称单数形式.如：
(1) Where is your fork and knife?你的刀叉在哪儿?
(2) Is the bread and butter enough for you two?你们两人吃这一点面包和黄油够了吗?
如不是被作为整体,则用复数.如；
Reading and writing are not the same.

我理解你的意思。比如说：
1 Teaching and learning are different things. -------这里teaching and learning是两件不同的事情，所以谓语动词是复数概念are.
2 Teaching and learning is the major business of a school.-------在这里，teaching...