50CrVA钢气阀螺旋弹簧水淬后应在（）内回火。 A.4h B.8h C.12h D_爱下问搜题

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问题单项选择题

50CrVA钢气阀螺旋弹簧水淬后应在（）内回火。

A.4h

B.8h

C.12h

D.24h

答案

参考答案：A

连线题

选选认认。

愉榆描瞄址趾帐账

树快准图脚地号篷

补全对话，情景问答

从B栏中找出与A栏中各句相应的答语。

              A
( )1. Are you free this Sunday?
( )2. Would you like to come to Songtao?
( )3. What are your favorite animals?
( )4. What time is it?
( )5. What's wrong with you?

            B
A. It's two to two.
B. Yes. What's up?
C. I can't find my way home.
D. Yes. I'd love to.
E. Pandas.