关于英语单复数的问题Bacon and eggs is my favourite breakfast.The dog and cat are playing.为什么第一个用is,第二个用are?

关于英语单复数的问题Bacon and eggs is my favourite breakfast.The dog and cat are playing.为什么第一个用is,第二个用are?
关于英语单复数的问题
Bacon and eggs is my favourite breakfast.
The dog and cat are playing.
为什么第一个用is,第二个用are?

关于英语单复数的问题Bacon and eggs is my favourite breakfast.The dog and cat are playing.为什么第一个用is,第二个用are?
Bacon and eggs代表咸肉煎蛋,是一个整体,后面用is,不要被迷惑了
The dog and cat代表狗狗和猫猫在玩,是两种动物用复数,
如果是My favorite animal is dogs这种情况下狗狗是一个整体性名词