Trichostomum

例句：

1. 1.The trematodes are the larvae of many parasitic flatworms.
   许多寄生虫的幼虫都是扁形虫。
2. 2. The trematodes have a complex life cycle involving several intermediate hosts.
   扁形虫有一个复杂的生命周期，涉及几个中间宿主。
3. 3.Trematodes are responsible for a variety of diseases in humans and animals.
   扁形虫对人类和动物造成各种疾病。