every boy and girl是单数还是复数
是用单数。every后面的谓语动词用单数,这是语法规定
例句
Every boy and girl is treated in the same way.
每个男孩，女孩都是以同样的方式对待的。
Every boy and girl in Britain has read it.
英国的每个男孩和女孩都读过它。
Every boy and girl knows that.
每个男孩和女孩都知道那件事。
And so, there ought to be one fairy for every boy and girl.
所以，世界上有一个孩子，就应该有一个小仙女。