常用车刀的材料有（）和（）两大类.
参考答案：高速钢、硬质合金钢
— Mr. Smith was really helpful when you were in financial difficulty during those years.
— Definitely. I can never appreciate his kindness ________.
A．seriously
B．well
C．enough
D．properly
黄芩清肺汤功效与作用
