英语语法分析

Collect cases:collected 60 cases SOM by policlinic random and 20 cases normal person;

采集病例：门诊随机搜集60例分泌性中耳炎和20例正常人的对照资料；

The most needed institutions were the special policlinic and school of special education.

最需要的服务机构是专科门诊、特殊教育学校。

The normal group were composed of 20 healthy children checked in the policlinic, age 2~14 years.

对照组为经过体格检查为正常健康儿童，年龄在2～14岁，共20例。