问题 单项选择题 B1型题

理想的上颌前牙冠桩直径为根管径的()。

A.2/3

B.1/5

C.1/4

D.1/3

E.1/2

答案

参考答案:D

解析:

桩过细,易折断;桩过粗,则牙根易折断,所以必须把握好桩的直径。年轻恒牙时,根髓腔大于或等于1/3根径,但有机物含量多,正常情况下不会发生根折;随着年龄的增长,髓腔逐渐变小,继发牙本质增多,根管壁越来越厚,正常情况下也不会发生根折。所以桩的直径一般不超过根径的1/3是安全的。故1,2题答案均为D。

阅读理解

阅读表达。

阅读下面短文,请根据短文后的要求进行答题.(请注意问题后的字数要求)

[1]Pupils at schools in the UK are being given lessons on how to sleep.The project,run by the charity

Sleep Scotland,aims to teach pupils tips,such as the importance of a bedtime routine and avoiding

late-night television.

[2]Experts say teenagers who seem bad-tempered could actually lack sleep because they go to bed

after midnight.The advice for pupils is that they should sleep for more than nine hours a night.Researchers

found that after going to bed after midnight,teenagers still _____________for watching television or

browsing the Internet.Some pupils were getting as little as four or five hours of sleep a night.

[3]One of the schools taking part in the project is Bellahouston Academy in Glasgow.Fiona Patterson,

head of the school's Health and Well-being Department,said the survey results were absolutely shocking.

"They can't function on so little sleep," she said.

[4]Sleep Scotland says getting enough sleep helps with academic performance and sporting skills.

However,going without enough sleep can be linked to obesity (肥胖) and a greater risk of depression.

Jane Ansell,director of Sleep Scotland,said,"You wouldn't send somebody to school without having the

right amount of food,so why would you send them without enough sleep?"

[5]A spokesman for Glasgow City Council said,"We are determined to provide guidance for young

people,so they can get the right amount of sleep and make the best of their learning potential."

1.What's the text mainly about? (Please answer within 10 words)

_________________________________________________________________________

2.Which sentence in the text is the closest in meaning to the following one?

People who lack sleep can easily gain weight and feel depressed,though.

_________________________________________________________________________

3.Fill in the blank in Paragraph 2 with proper words.(Please answer within 6 words)

__________________________________________________________________________

4.What are the benefits of getting enough sleep? (Please answer within 10 words)

__________________________________________________________________________

5.Translate the underlined sentence in Paragraph 5 into Chinese.

____________________________________________________________________

单项选择题