What does the author imply with the movie Sideways？
A. Happiness can be found through pains and efforts.
B. Happiness comes when everything dies.
C. Happiness makes sadness deeper.
D. Happiness is not a good thing.
普通混凝土划分()个等级，最高等级为()。
A. 12，C60
B. 13，C80
C. 14，C80
D. 13，C60
混凝土的抗拉强度只有抗压强度的()。
A. 1/5～3/5
B. 1/20～1/10
C. 3/10～7/20
D. 1/30～l/20
不锈钢是指含铬量在()以上的铁基合金钢。
A. 10%
B. 12%
C. 15%
D. 20%
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