Had the doctor not been sent out at once, the boy who was knocked down by a pass

题型：不详难度：来源：

Had the doctor not been sent out at once, the boy who was knocked down by a passing
A                  B                                             C
car would not have been saved.
D

答案

B  been sent out ---been sent out for

解析

sent out for a doctor是固定搭配，意思是：去请医生。