为什么Tomatoes are healthy food（西红柿是健康的食品 ）Tomatoes 用复数,而Candy is a healthy food（糖果是健康的食品 ）Candy用单数?

On the table there are five_________.A.tomatos B.picec of tomatoes C.tomatoes 为什么不能选B? Heal heal I prefer sandwiches to tomatoes--tomatoes are gross 翻译. My favorite food ( ) tomatoes and bananas.请问括号中填is 还是are,为什么? Tomatoes are a kind of vegetable.为什么这里 are 后面是 a kind ,系动词与表语不一致吗? We haven't got many tomatoes,为什么不用 any tomatoes Are these red tomatoes yours?《肯定句》 these are tomatoes改为一般疑问句 Those tomatoes are (￥6)对括号提问 Tomatoes are good vegetable还是vegetables? are those tomatoes肯定回答是什么 Potatoes and tomatoes are v什么 什么are these tomatoes?They are 2 yuan a kilo. 为什么Tomatoes are healthy food（西红柿是健康的食品 ）Tomatoes 用复数,而Candy is a healthy food（糖果是健康的食品 ）Candy用单数? there are some tomatoes in the bag.对some tomatoes提问. Tomatoes are my favourite food .和My favourite food is tomatoes.这两句话对吗 是how many box of tomatoes are over there?还是how many boxes of tomatoes?