一个英语语法问题.为什么need和contain后面要加S?而有些不用呢?
Evry person (needs) water and a diet of healthy foods.These foods should (contain) some fat,some fibre,a little salt and so on.
It (contains) a lot of fruit and green vegetable.
People (need) energy to live.
大家请注意最后一句：People need energy to live.这里People是复数但是为什么need后面却不加S？