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【简答题】
咖啡酸（下式中的A）是某种抗氧化剂成分之一，A与FeCl3溶液反应显紫色。
咖啡酸可看作l，3，4-三取代苯，其中两个相同的官能团位于邻位，取代基中不含支链。则咖啡酸的结构简式为（）
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】If those "mad moments"— when you can’t recall what your friend has told you or where you left your keys—are becoming more frequent, mental exercises and a healthy brain diet may help. Just as bodies r...
A.
everyone can be forgetful sometimes regardless of one’s age
B.
we can prevent our sound mind from aging with certain methods
C.
brain aging starts from the time when we are in our 20s and 30s
D.
memory loss is a sign that shows we are getting old