单选题:5,7-二甲氧基黄酮的

题目内容:
5,7-二甲氧基黄酮的 A.1H-NMR中化学位移在12.50左右有吸收
B.1H-NMR中H-8比H-6在低场有吸收
C.1H-NMR中A环上没有芳香质子
D.1H-NMR中A环具有一个芳香质子
E.1H-NMR中A环质子具有ABX偶合系统

参考答案:【答案仅供学习,请勿对照自行用药等】
答案解析:

Passage One.听材料,回答下列各题:What were the scientists worried abou

Passage One.听材料,回答下列各题:What were the scientists worried about soon after the G

查看答案

Conversation Two.听材料,回答下列各题:What does the man want to do acc

Conversation Two.听材料,回答下列各题:What does the man want to do according to the conv

查看答案

Which of the following did the man agree to do?

Which of the following did the man agree to do?A.He will postpone the trip. B.He

查看答案

属于紫芝的性状特征的是

属于紫芝的性状特征的是A.皮壳坚硬,黄褐色或棕红色,有光泽 B.纵切面紫黑色 C.皮壳与菌柄表面紫黑色,有漆样光泽,菌肉锈褐色 D.皮壳外有大量粉尘样黄褐色孢子

查看答案