You'd better cut your hair short. Our school doesn't _____ long hair.[       ]

A. approve of students wearing

B. approve students to wear

C. approve students wearing

D. approve of students to wear

钢在热加工变形中，夹杂物也随之一起变形，沿加工方向延伸呈条带状，这类夹杂物叫（）夹杂物。

A、脆性

B、点状

C、塑性

D、硬性