The () () is fish and meat in our countryside.

The () () is fish and meat in our countryside.
中文：在我们乡下,主菜一般是鱼和肉.
我纠结的是,括号里不知道该填main dish还是main dishes.望高手解答.
还有一个小题：Her favorite food is patatoes.这个句子是对的吗?我搞不清楚到底是用is还是用are.
打错了，Her favorite food is patatoes应该是Her favorite food is potatoes.