注意：
and, both...and 连接两个可数名词时，一般谓语用复数;or, either...or, neither...nor, not only...but also...谓语的数以谓语自身旁边的主语为准。
Both salt and sugar dissolve easily. 盐和糖均易溶解。
Not only the students but also the teacher is enjoying the film. 不仅学生而且老师都在津津乐道地看着电影。
Neither the students nor the teacher knows anything about it. 同学们和老师对此都一无所知。
Neither he nor they are wholly right. 他和他们，谁都不是完全对的。
Either he or I am right. 或者他对，或者我对。
