合金元素在钢中可以两种形式存在：一是溶解于铁素体中形成合金铁素体，另一种是与碳化合形成合金碳化物。
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Q295A表示屈服极限不低于295MPa，质量等级为A级的普通碳素结构钢。
A. 对
B. 错
GCr15表示平均含铬量为15%滚动轴承钢。
A. 对
B. 错
This book is______ that one, but______ than that one.
A. as difficult as; expensive
B. as more difficult as; more expensive
C. as difficult as; more expensive
D. more difficult as; as expensive
It was very hot yesterday, but it is_______ today.
A. even hotter
B. more hotter
C. much more hot
D. much hot
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