下列高聚物中结晶能力最弱的是()
A.聚乙烯
B.聚四氯乙烯
C.聚氯乙烯
D.聚偏二氯乙烯
参考答案:C
_____ of the soldiers are young people. [ ]
A. Two third
B. Two thirds
C. Second three
D. Two threes
笔记本电脑外壳多采用优质的ABS工程塑料,这主要是利用厂这种塑料的 [ ]
A.硬度大
B.磁性强
C.密度大
D.导电性好