通过回火能提高钢的（）。
A.抗氧化性
B.韧性
C.耐腐蚀性
D.化学稳定性
参考答案：B
Hu Mei, ___ daughter of a teacher’s family, was made ___ monitor of the class at the meeting.
A．the; a
B．the; 不填
C．a; the
D．the; the
气压的单位是（）。
A.千克/米3
B.千克力/米2
C.千克秒/米2
D.升/米2
