---about the student,the teacher called his parents to find out why he was so often absent from

问题描述:

---about the student,the teacher called his parents to find out why he was so often absent from
class.
A、concering B、 concerned 为什么选b?我不懂.

补全你就知道了.
【As they were 】concerned about the student,.
be concerned about .关心.