问题
单项选择题 A1/A2型题
盐酸-镁粉反应通常呈阳性的是（）
A.儿茶素
B.黄酮
C.异黄酮
D.查耳酮
E.二蒽酮
答案
参考答案：B
解析：黄酮、黄酮醇、二氢黄酮类化合物盐酸一镁粉反应呈阳性；查耳酮、儿茶素无该颜色反应；异黄酮除少数例外，也不显色。
搜题请搜索小程序“爱下问搜题”
盐酸-镁粉反应通常呈阳性的是（）
A.儿茶素
B.黄酮
C.异黄酮
D.查耳酮
E.二蒽酮
参考答案：B
解析：黄酮、黄酮醇、二氢黄酮类化合物盐酸一镁粉反应呈阳性；查耳酮、儿茶素无该颜色反应；异黄酮除少数例外，也不显色。
It is possible that the majority of the teenagers accepted the advantages of the iPad. In most cases they were expressing strong opinions about it. But today we already know that another three high-end computer tablets(平板电脑) are going on sale, with the aim of taking a bite out of the iPad's market. For tablet computer fans, iPad may not be the only choice, as the Motorola Xoom, the HP Touchpad and the BlackBerry PlayBook will have been launched (推出)by this summer, according to foreign media reports on Tuesday. Here is Product Information Guide as follows. We would like to listen to your reviews later.
A. Apple ipad 2 has excellent data security. B. Four t  ypes above of Battery life are the same.C. Most people are satisfied with HP Touchpad. 小题3: Which one can you buy as a present with only 4000yuan RMB at  hand?
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