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一、一道考查学生审题能力的好题向盛有一定淀粉溶液的试管中加入适量的唾液淀粉酶,37℃水浴保温后,先后加入适量的0.1 g/mL的NaOH溶液和0.01 g/mL CuSO4溶液,摇匀后,观察试管内溶液变化的现象是().A.产生砖红色沉淀B.溶液呈蓝色C.溶液呈现紫色D.溶液不变化此题看似简单,但学生要正确解答实则不易,本题正确率只有15%.统计的班级共47人:选A、B、C、D的人数分别为18
First, a test of the ability to examine the problem a good question A certain amount of starch solution containing test tube tube of saliva amylase, 37 ℃ water bath after the heat, was added by the appropriate amount of 0.1 g / mL NaOH solution and 0.01 g / mL CuSO4 solution , Shake well, observe the phenomenon of the solution in the test tube change (). A. produce brick red precipitate B. solution was blue C. solution purple purple D. solution does not change This question may seem simple, but the students to correct answer, but in fact Not easy, the correct rate of this question is only 15% .A total of 47 people in the statistics: choose A, B, C, D, respectively, the number of 18