分析子成分 The doctor did his best to do what he could to help the sick boy .
问题描述：
分析子成分 The doctor did his best to do what he could to help the sick boy .
主要说明 he could 是什么成分
答
the doctor是主语,did是谓语.后面是一个有what引导的宾语从句,整个句子做宾语.宾语从句里he做主语,could为谓语,what引导词做宾语.