维修作业进度控制
参考答案：
是指在维修作业执行过程，对有关配件加工的数量和维修作业进度进行的操纵。
已知|a-2|+|b+4|=0，则a+b=______．
Father doesn’t know Jack has been gambling; if he found out, I think he him out.
A．will drive
B．must drive
C．drove
D．would drive
