We usually drink tea and eat nuts for snacks?请问句中nut为什么要加s,s

We usually drink tea and eat nuts for snacks?请问句中nut为什么要加s,s we go though ups and downs together此句中up down为什么要加s 为什么Eat lots of fruit and vegetables中fruit不加s,而vegetable加s, 你疯了吗是：Are you nuts?还是Are you nut?用不用加s 为啥? we eat lots of vegetables and fruit 为什么fruit不加s usually read newspaper 中 newspaper要加s吗?为什么 we know that tigers eat meat tiger为什么加S 请问这句英语,He eats another apple 中的eat为什么要加S 还有我可不可以 Juice and water are healthy drinks,drink为什么要加s,water ,juice, we have been best friends for a long time中friends为什么要加s for lunch and dinner ,i usually eat fish and vegetables.此句中d eat 吃和drink 喝什么时候加s