题目

When Spring Festival comes, there are many sales in my city, during _____ time stores will lower their normal prices. A. whose           B. that              C. which          D. its   答案：C  考查定语从句。which time 代指先行词Spring Festival，前面加上介词during，表示“在春节期间”的意思，during which time在句中作状语。  右图是甲、乙两种物质（不含结晶水）的溶解度曲线。下列说法中不正确的是 A．t1℃时，50g甲的饱和溶液中有15g甲B．t2℃时，等质量的甲、乙的饱和溶液降温到t1℃，所得的溶液中甲的质量小于乙的质量C．要使甲的饱和溶液变为不饱和溶液，可采用升高温度的方法D．当甲中含有少量乙时，可以用降温结晶的方法提纯甲