英语句型中的疑问

问题描述:

英语句型中的疑问
Quails typically have short rounded wings that enable them to spring into full flight instantly when disturbed in their hiding places.when disturbed in their hiding places 中的 disturbed 为被动形式,但是前面为什么没有系动词?

此处是省略句,省略了they was .when they was distrubed·····当特殊疑问词引导从句时,前后主语一致可以省略从句中的主语和谓语