题型:填空题 Jack won the first prize in yesterday’s English speech competition and he was so excited that he didn’t _______until late into the night.A.bring downB.set downC.take downD.settle down 查看答案
题型:填空题 电弧焊在焊接方法中之所以占主要地位是因为电弧()转换成熔化焊接过程所需要的热能和机械能。A.能有效而简单的把光能B.能有效而简单的把电能C.能有效而简单的把化学能D.能有效而简单的把光能和机械能 查看答案