重碳酸根HCO3-含量的高低,决定了天然水的碱度的大小。()
参考答案:对
简要分析曹操在官渡之战和赤壁之战中出现两种结果的原因。
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编织物在紫外线的照射下,高分子会发生(),产生降解,使编织物老化。
A.聚合
B.交联
C.断链
D.共聚