轮虫

例句：

1. 1. The larva of a roundworm can live for up to three years.
   一种轮虫的幼虫可以活长达三年。
2. 2. Roundworms are common parasites that infest humans and animals.
   轮虫是常见的寄生虫，寄生于人类和动物体内。
3. 3. In the lab, scientists use microscopes to study the behavior of roundworms.
   在实验室里，科学家们使用显微镜研究轮虫的行为。