Too much bread and butter ______not good for you.(is/are)

题目

Too much bread and butter ______not good for you.(is/are)
请说明为什么填这个答案
我认为应该选are,因为主谓一致似乎两个不可数应用复数形式
但答案说选is（新概念二册第90课练习）

答案

并列主语如果指的是同一个人、同一事物或同一概念时,谓语动词用单数形式,这时and后面的名词没有冠词.如：Truth and honesty is the best policy.The girl’s teacher and friend is a young doctor.To love and to b...