- - How dangerous it was!

- - Yes, but for the passer - by' s quick action, the child _____．

A．was drowned

B．could have been drowned

C．had been drowned

D．should have drowned

焊缝和热影响区性能最好的焊接方法是______。

A．气焊

B．焊条电弧焊

C．埋弧自动焊

D．手工钨极氩弧焊