Was it in this very room ____ he made up his mind ____ he should break away from his family?

A．that; which

B．which; that

C．which; which

D．that; that

成型工序是指坯料受外力后，应力超过了材料的屈服点，经过（）变形成为一定形状的加工工序。

A.弹性

B.塑性

C.韧性