根据《混凝土结构设计规范》(GB 50010—2010)的规定,钢筋混凝土结构的混凝土强度等级不应低于( )。
A.C20 B.C15C.C25 D.C30
参考答案:B
What a pity. Considering his ability and experience, he ____ better.
A.need have done
B.must have done
C.can have done
D.might have done
根据PEST分析法,人民消费结构和消费水平属于组织的()环境。
A.技术
B.经济
C.社会文化
D.政治法律