A. 正确 B. 错误
A. 点划线 B. 折断线 C. 波浪线 D. 虚线
A. haven't seen B. didn't see C. hadn't seen D. don't see
A. 磨损率越底 B. 磨损率越高 C. 弹性越好 D. 强度值越大