她对贝类过敏，所以不能吃螃蟹和牡蛎。

She's allergic to ___shellfish, so she can't eat crab or oysters.

这家餐厅以新鲜的海鲜闻名，尤其是各种贝类。

This restaurant is famous for its fresh seafood, especially various types of ___shellfish.