焊接应力和（）在焊接时是必然要产生的，是无法避免的。
参考答案：焊接变形
He was a young man of barely eighteen years, evidently country, and now, as it seemed, on his first visit to town.
A．brought up
B．bred
C．grown up
D．raised
高炉冶炼对矿石品位的要求是（）。
A.高
B.低
C.高稳
D.低稳
