both and若连接两个不同的不可数名词,主语算单还是复?

are
用and或both and连接的两个名词（或成分）作主语时,谓语动词用复数形式,如：
Both bread and butter were sold out in that grocery.
上面那个句子是我语法书上的,也是两个不可数名词,正好~