乌龟们有壳的英文是 "turtles have shells."

"Shell" 这个词的来源可以追溯到古英语 "scealu" 或 "sceall"，它有 "hard outer covering" 的意思。"Turtle" 这个词来源于古英语 "tortise"，表示 "a reptile with a hard, bony or leathery shell."

下面是一些例句：

Turtles have shells to protect themselves from predators. (乌龟有壳是为了保护自己不被捕食者吃掉。)
The turtle's shell is made up of bony plates that are fused together. (乌龟的壳是由融合在一起的骨板组成的。)
I saw a turtle with a bright yellow shell at the beach. (我在海滩上看到了一只有黄色壳的乌龟。)