搜题请搜索小程序“爱下问搜题”
问题 单项选择题

为防止游离酸对牙髓的刺激，年轻患者的恒牙（活髓牙）采用铸造全冠修复时，不能用的永久性粘固剂是（）

A.磷酸锌粘固剂

B.玻璃离子体粘固剂

C.树脂粘固剂

D.羧酸玻璃离子粘固剂

E.合成高分子化合物粘固剂

答案

参考答案：E

解析：合成高分子化合物黏固剂对年轻恒牙（活髓牙）刺激性强。

选择题

草木灰的主要成分是K2CO3，其中碳元素的化合价为（　　）

A．+1

B．+2

C．+3

D．+4
查看答案
句型转换

句型转换：根据要求转换下列各句，每空一词。

1. He is tall and always wears a pair of glasses.  (对划线部分进行提问) 

                 does he look            ?

2. Kitty is 15 years old. John is 13 years old.  (合并成一句)

    Kitty is                            John.

3. Simon has the most paper clips in his class.  (改为同意句)

    Simon has             paper clips than any              student in his class.

4. My book is more interesting than his book.  (改为同意句)

    His book                            interesting as my book.

5. You must not play football in the street.  (改为祈使句) 

                                 football in the street.

查看答案