题型:选择题 His essay, ____many times,was brief and to the point,and therefore won the first prize in the writing competition.A.polishing upB.having polished upC.to be polished upD.having been polished up 查看答案
题型:填空题 下图是甲、乙两种固体物质的溶解度曲线,试回答下列相关问题。 (1)t1℃时,100g水中溶解20g甲,溶液刚好饱和,则t1℃时甲物质的溶解度为 g。 (2)t1℃时,若要将甲物质的饱和溶液变为不饱和溶液,可采用的方法是 (写出一种即可)。 (3)t2℃时,比较两物质的溶解度大小:甲 (选填“>”或“<”或“=”)乙。 查看答案