对于投诉应填写（）
A.维修工单
B.投诉处理表
C.预约单
D.返修单
参考答案：B
.The school meeting ________ once every two weeks in the concert hall.
A．is held
B．was held
C．will be held
D．has been held
冲击试验有何作用？怎样测定？
