目前，最常用的冷作模具钢属于高碳高铬模具钢，有Cr12、Cr12MoV冷作模具钢。
查看答案
高速工具钢锻造后必须进行退火，目的在于消除应力，降低硬度，使显微组织均匀，便于淬火。
A. 对
B. 错
Listen to news report 1 and answer 2 questions.What does the news report say about Ali MacGraw and Ryan O’Neal?[音频]
A. They used to be classmates at Harvard University.
B. They became household names because of the film Love Letters.
C. They are on a national tour for their play Love Letters.
D. They are reunited to celebrate the success of their film Love Story.
What do we learn about the film Love Story ?
A wealthy Harvard young lady married a poor young man.
B. The young man in the film got a disease and died.
C. It received six Academy Award nominations.
D. “Love means never having to say you’re sorry” is often used nowadays.
Listen to news reoprt 2 and answer 2 questions.How many couples were present at the Saturday ceremony?[音频]
A. 1,087.
B. 1,080.
C. 1,211.
D. 1,201.
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