Customers say the food at the restaurant tastes terrible.这句话中的tastes为何用第三人称单数?

Customers say the food at the restaurant 【tastes】 terrible.翻译：一些人说这个饭店的食物味道很糟糕.解析；【the food at the restaurant tastes terriblethe food 】 宾语从句,从句主语food,是第三人称单数,...