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问题 单项选择题

山柰酚属于

A．黄酮类

B．黄酮醇类

C．二氢黄酮类

D．二氢黄酮醇类

E．查耳酮类

答案

参考答案：B

解析：黄酮醇类的结构特点是在黄酮基本母核的3位上连有羟基或其他含氧基团，如山柰酚、槲皮素。

填空题

用括号内所给动词的适当形式填空。

1. Betty is often seen ______ (help) the old man with his housework.

2. He prefers ______ (take) part in the public activities rather than stay at home alone.

3. They ______ (agree) with each other, so they argued for a long time.

4. Animals are our friends, so ______ (protect) them is our duty.

5. You have ______ (award) a scholarship to study violin at our school of music.

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选择题

X、Y、Z、W是四种不同的金属，为比较金属活动性的大小，某同学利用这四种金属单质、盐酸、Z的硝酸盐、W的硝酸盐，进行有关实验，结果如下表（能反应的记为“+”，不能反应的记为“-”，无标记的表示未做该实验）．则这四种金属的活动性顺序为（　　）

XYZW
盐酸-+-+
Z的硝酸盐+++
W的硝酸盐-+-

A．Y＞W＞X＞Z

B．W＞X＞Y＞Z

C．X＞Y＞W＞Z

D．Y＞W＞Z＞X
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