cases

例句：

1. 1. The police are investigating the cases of missing persons.
   警方正在调查失踪人员案件。
2. 2. The doctors have found several cases of malaria in the area.
   医生们在该区域发现了几起疟疾病例。
3. 3. This case is a classic example of how to handle a difficult situation.
   这个案例是处理棘手情况的经典例子。