【单选题】以下关于高速钢说法错误的是( )。
A.
一般含有钨、钼、铬等合金元素,总量超过10%
B.
耐热性不足,作为刀具材料在切削加工时需要充分的冷却
C.
W18Cr4V一般用于制造普通车刀、铣刀、刨刀、钻头等
【单选题】____ the fight stopped, travel across the country has been quite safe.
【单选题】His grandparents used to ________ a walk after dinner, but now they are used to ________ a walk after breakfast.
【单选题】He used to to school by bike but he is used to to school now.
【单选题】___the fight stopped, travel across the country has been quite safe.
【单选题】在1970年,哪位学者曾研制出用以测量浪漫爱情层次的量表。