specific pathogen free animals

例句：

1. 1. SPFanimals are used in research to study theeffects of radiation on living organisms.
   SPF动物用于研究辐射对活体生物的影响。
2. 2. The researchers conducted experiments on SPF animals to test their immunity to thevirus.
   研究人员对SPF动物进行实验，以测试它们对病毒的免疫力。
3. 3.The SPF animals were carefully monitored toensure they were healthy and free from anydiseases.
   这些SPF动物被仔细监控，以确保它们健康且没有疾病。