history of preventive inoculation

例句：

1. 1. The vaccineis designed to prevent the spread of thedisease.
   这种疫苗旨在预防疾病的传播。
2. 2. Preventive measures are taken to reduce therisk of accidents.
   采取预防措施以减少事故的风险。
3. 3. The company's policy isto provide preventive maintenance for all itsequipment.
   该公司的政策是为所有设备提供预防性维护。