题目

Mike and his friend are going to the           to see the new action movie tonight。  A．book shop          B．concert           C．cinema 答案：C在做“提取DNA实验”时，某学生试图用人血代替鸡血，没有成功，原因是 A．操作方法不对B．人血含DNA太少C．NaCl溶液浓度太高 D．加二苯胺太少