Seafood是不可数名词。因为Seafood的意思指所有的海鲜食品(即泛指)，不能以数目来计算，所以不可数。例句：Seafood unsettles my stomach.我一吃海鲜胃就不舒服。
双语例句
1、Try the seafood plate.
请尝尝这道海鲜。
2、Seafood is a speciality on the island.
海味是岛上的特产。
3、The fish or seafood is heavily salted with pure sodium chloride.
鱼或海鲜被抹了厚厚的纯盐腌制起来。
4、Seafood soup is a good appetizer.
海鲜汤是一道很好的开胃菜。
5、The common prescription is to primarily shop the grocery store, since that's where fresh produce, meat and seafood, and dairy are.
通常的方法是主要在杂货店采购，因为那里有新鲜的农产品、肉类和海鲜以及奶制品。