题目

11．16．When did the story happen？A．Last Wednesday．B．Last Friday．C．Last Saturday．17．Why couldn't Jack's parents stay with them？A．They were busy shopping．B．They were busy visiting friends．C．They were busy working．18．What was Jack doing while his grandmother was cooking？A．Watching TV．B．Sleeping．C．Reading newspapers．19．Whom did Jack ask for help？A．Mr．Black．B．Mr．Smith．C．Mr．Brown．20．How long did it take them to get to the hospital？A.12 minutes．B.15 minutes．C.20 minutes．下列试剂与鉴定的物质及颜色变化的对应关系正确的一组是A. 双缩脲试剂-蛋白质-紫色；健那绿染液-线粒体-灰绿色B. 碘液-淀粉-蓝色；重铬酸钾溶液-酒精-蓝绿色C. 甲基绿-DNA-绿色；斐林试剂-麦芽糖-砖红色D. 醋酸洋红染液-染色体—红色；苏丹IV染液-脂肪-橘黄色