问题 单项选择题 A1/A2型题

以下水门汀可与牙体组织形成化学性结合的是()

A.氧化锌丁香酚水门汀

B.磷酸锌水门汀

C.聚羧酸锌水门汀

D.玻璃离子水门汀

E.C和D

答案

参考答案:E

解析:聚羧酸锌和玻璃离子水门汀除能与牙和修复体形成机械嵌合力外,还可与牙体组织形成化学性结合。聚羧酸锌水门汀与牙体组织的化学性结合力来源于:未反应完的-COOH与牙表面的-OH形成氢键,并与牙中的Ca发生一定程度的络合反应,而已离解的COO可与牙中的Ca产生一定的异性离子吸引力。对于玻璃离子水门汀,每个羧酸盐基团在玻璃粉表面取代了一个磷酸盐基团和一个Ca,使羧酸盐基团与羟基磷灰石表层有效结合。

阅读理解

My house is made out of wood, glass and stone. It is also made out of software.

If you come to visit, you’ll probably be surprised when you come in. Someone will give you an electronic PIN (个人身份号码)to wear. This PIN tells the house who and where you are. The house uses this information to give you what you need. When it’s dark outside, the PIN turns on the lights nearest you, and then turns them off as you walk away from them. Music moves with you too. If the house knows your favorite music, it plays it. The music seems to be everywhere, but in fact other people in the house hear different music or no music. If you get a telephone call, only the nearest telephone rings.

Of course, you are also able to tell the house if you want something. There is a home control console (控制台), a small machine that turns things on and off around you.

The PIN and the console are new ideas, but they are in fact like many things we have today. If you want to go to a movie, you need a ticket. If I give you my car keys, you can use my car. The car works for you because you have the keys. My house works for you because you wear the PIN or hold the console.

I believe that ten years from now, most new homes will have the systems that I’ve put in my house. The systems will probably be even bigger and better than the ones I’ve put in today.

I like to try new ideas. I know that some of my ideas will work better than others. But I hope that one day I will stop thinking of these systems as new, and ask myself instead, “How will I live without them?”

小题1:What does the passage mainly discuss?

A.How to develop a new system.

B.The function of the PIN.

C.A home for the future.

D.Easy life in the future.小题2:What’s the purpose when the writer wrote the fourth paragraph?

A.To let readers know why his ideas are new.

B.To let readers know how special his house is.

C.To explain the importance of the PIN and the console.

D.To explain more easily what the functions of the PIN and the console are.小题3:The writer’s new house is different from ordinary ones mainly because _____.

A.it has been controlled by computers

B.you can make a telephone call anywhere

C.it has your favorite music following you

D.the writer is able to change his new idea into practice小题4:What is the writer most likely to be according to the passage?

A.An IT expert.

B.A famous doctor.

C.An idealist

D.An experienced teacher.小题5:What can’t be done in the writer’s new house?

A.turns on the lights

B.play music

C.get a telephone call

D.go swimming

单项选择题