【判断题】钢材的焊接质量主要与焊条有关,与钢材成分关系不大。( )
【简答题】(10分)电解铝技术的出现与成熟让铝从皇家珍品变成汽车、轮船、航天航空制造、化工生产等行业的重要材料。工业上用铝土矿(主要成分为Al 2 O 3 ,Fe 2 O 3 、SiO 2 等)提取纯Al 2 O 3 做冶炼铝的原料,某研究性学习小组设计了如下提取流程图: (1)固体Ⅱ的化学式为_ ____,该固体的颜色为 ; (2)写出流程③的离子方程式 ; (3)铝粉与氧化铁粉末在引燃条件下常用来焊接钢...
【单选题】. --- Mr Smith, __________ girl wants to see you. --- If that’s __________ girl who has fair hair and wears a red dress, I want to see her.
【单选题】3, 10, 21, 35, 51, ( )
【简答题】直接写得数. 51÷3= 990-99= 26×4= 59+41= 990÷11= 90÷6= 95÷5= 480÷8= 300-157= 3×43= 45万+67万= 9×8÷9×8=
【简答题】比较大小。 34+5○5+34 59-5○51+5 88-8○99-9 24+3○28-3
【简答题】When someone gets near, an armadillo will go down its retreat, and then it is very difficult to ______.
【判断题】收款凭证、付款凭证是用来记录现金和银行存款收付业务的记账凭证,它们根据有关现金和银行存款收付业务的原始凭证填制。( )(2.0分)
【单选题】Big cites today are confronted with very serious problems. Transport is a【C1】______difficulty: some planners believe in【C2】______transport system;others believe in making it possible for citizens to m...