产品（部件）为矩形时的不矩程度称为（）。
A、翘曲度
B、平整度
C、位差度
D、邻边垂直度
参考答案：D
精矿的重量与原矿重量之比叫富矿比。
Paramedics were able to__________ his heart and get him breathing before airlifting him to hospital.
A．repeat
B．regain
C．restart
D．review
