合金结构钢的牌号中,前面的两位数字表示钢的平均含碳量的( ),元素符号后的数字表示所含合金元素的( )。
A. 万分之几、百分之几
B. 千分之几、千分之几
C. 百分之几、万分之几
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W18Cr4V 属于( )。
A. 灰铸铁
B. 合金工具钢
C. 不锈钢
在室温下,20、45、T8及T12钢,其含碳量依次增加,强度、硬度依次升高,塑性、韧性依次降低。
I am interested in the training course, which ______ at Hilton Hotel in Beijing from March 8 to 12 next year.
A. held
B. was held
C. will hold
D. will be held
______ traveling expenses rising a lot, Ms. White had to change all her plans for the tour.
A. Since
B. As for
C. By
D. With