A:浓盐酸久置于空气中,溶液质量会变小
B:铁制品表面涂油可防锈
C:煤块粉碎后燃烧的目的是为了减少二氧化碳的排放
D:用燃烧法区分棉纤维和羊毛纤维
— Did you study any other languages English when you were at college?
— Yes, I studied three. But I have forgotten all a few words of each.