问题 单项选择题 A1/A2型题

下列对于酸蚀作用描述,错误的是()。

A.可去除表层玷污釉质

B.增加釉质表面自由能

C.活化釉质表层

D.酸蚀牙本质不会造成牙髓损伤

E.增加牙的表面积和粗糙度

答案

参考答案:D

解析:基于釉质的成分和结构特点,复合树脂对釉质的粘结主要采用酸蚀技术,即通过酸蚀刻釉质表层,获得树脂修复的微机械固位,从而增强复合树脂与釉质粘结强度的方法。其作用主要为A、B、C、E。酸蚀釉质对牙髓不会造成损害,但酸蚀牙本质可通过牙髓牙本质复合体而激惹牙髓,重者可引起牙髓病变。

阅读理解

阅读理解。

     An old woman from the United States is helping develop a small Chinese village. She lived there when

she was a child.

     In the early 20th century, Eunice Moe Brokck's parents came to Shandong Province and they gave birth

to her there. As she grew up, Brock saw the poverty (贫困), illness and war in China. So when she left China

at the age of 13, she decided to come back to help the poor people there.

     After her husband died, the old woman sold her house, her car, her forest and other things and moved to

China in 1999. She lived in Liumiao Village in Liaocheng of Shandong Province to help the villagers there.

     Though she is now in her nineties, she is still busy helping them. In the past few years Brock built a

computer room for the village school with her own money, and bought desks, chairs and books for students.

She also has been trying to improve the medical care conditions in a number of villages. In Liumiao, every

child can play with toys in Brock's home. At Christmas she always buys a lot of candies and takes them to

schools for students.  

     "I'm an American, but I love China," she said.

1. Eunice Moe Brock was born _________.

A. in Shandong Province

B. in the United States

C. in the south of China

2. Brock returned to China _________ years ago.

A. nine

B. thirteen

C. twenty

3. From the passage we know that Brock is _________.

A. less than 90 years old

B. over 90 years old

C. a middle-aged woman

4. Which of the following is true?

A. Brock's husband died while she was in China.

B. The villagers got much money from Brock.

C. Brock has made a great contribution to the villages in China.

5. The best title for the passage is _________.

A. A Woman in China

B. A Poor Village in China

C. An American Woman with a Chinese Heart

单项选择题 A型题