一般情况下，冲裁件多选用（）的材料。
A.强度高
B.硬度高
C.强度低
D.硬度低
参考答案：D
计算机的输出设备主要有（）、绘图仪等。
A.显示器
B.键盘
C.鼠标
D.打印机
Tom's mother was always telling him what he should do, but _____ didn't help. [ ]
A. he
B. she
C. it
D. which
