_____ about Lucy,the teacher called her parents to find out why she was often absent from school.
问题描述：
_____ about Lucy,the teacher called her parents to find out why she was often absent from school.
为什么填Concerned,而不填To be concerned?
答
concerned about是分词短语作状语相当于 because the teacher was concerned about ,所以中保留过去分词形式,如果用后一种即不定式表示为了,即目地状语.本句显然表示原因.