氩弧焊特别适于焊接容易氧化的金属和合金,是因为()
A.氩弧温度高
B.氩气容易取得
C.氩弧热量集中
D.氩气是惰性气体
参考答案:D
The audiences’ reaction made it _____ that this play was a great success.
A.evident
B.familiar
C.relevant
D.skeptical.
—Oh, Mrs. Liu, your necklace looks nice. Is it new?
— No, I ____ it for two years.
A.had
B.have had
C.bought
D.have bought