A. the living standard came down B. came down the living standard C. down the living standard came D. down came the living standard
A. has looked B. has been looking C. looked D. was looking
A. three-years-old B. three years' old C. three-year-old D. three-year old
A. becomes B. become C. has become D. have become
A. 钢筋混凝土 B. 彩色涂层钢板制品 C. 石油沥青 D. 玻璃纤维增强塑料
A. ISO B. GB C. JG D. JC
A. 密度 B. 表观密度 C. 憎水性 D. 亲水性
A. >90° B. ≦90° C. >45° D. ≦180°
A. 耐久性 B. 强度 C. 保温性能 D. 导热系数
A. 松木、普通混凝土、低碳钢 B. 普通混凝土、低碳钢、松木 C. 低碳钢、松木、普通混凝土 D. 松木、低碳钢、普通混凝土
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