机床切削常用刀具材料有高速钢和()。
参考答案:硬质合金
清扫器皮带条应露出其金属夹板()mm。
A.10~14
B.5~10
C.15~20
D.10~20
A large part of human activity,particularly in relation to the environment,is conditions or events.
[ ]
A.in response to
B.in favor of
C.in contrast to
D.in excess of