fruit的复数形式是 fruits或fruit ,所以fruit and vegetables可以是水果和蔬菜(复数)；但是不管是不是复数,用and连接两个主语的谓语动词都用复数。
We buy our fruit and vegetables at the market.
我们在市场上购买水果和蔬菜。
Fruit and vegetables grew in abundance on the island.
该岛盛产水果和蔬菜。
Eat plenty of fresh fruit and vegetables.
多吃新鲜水果和蔬菜。
