【单选题】纯铜焊接时,常常要使用大功率热源,焊前还要采取预热措施的原因是( )。
【简答题】某一财产物资要成为企业的资产,其所有权必须属于企业。( )
【单选题】出土的锡青铜(铜锡合金)文物常有Cu 2 (OH) 3 Cl覆盖在其表面。下列说法正确的是
D.
生成Cu 2 (OH) 3 Cl覆盖物是电化学腐蚀过程,但不是化学反应过程
【单选题】纯铜是用电解法获得的,也称 “ 电解铜 ” ,在日常生活中我们称之为 ( )
【单选题】Now listen to the following recording and answer questions 19 to 21. 19.
A.
They are unsatisfied with their work.
B.
They need to take care of their children.
C.
They are in companies with loose management.
D.
They don’t take their work seriously.
【单选题】Questions 19 to 22 are based on the recording you have just heard . 21.
A.
It will work closely with the government .
B.
It will endeavor to write off bad loans .
C.
It will try to lower the interest rate .
D.
It will try to provide more loans .
【单选题】纯铜是最常用的导电、导热材料。它的( )非常好,易于冷、热压力加工。