患者男，56岁，双侧游离缺失，拟行可摘局部义齿修复，做基牙如果牙槽嵴吸收较重，则末端
题型：单项选择题 共用题干题
问题：
患者男，56岁，
双侧游离缺失，拟行可摘局部义齿修复，
做基牙
如果牙槽嵴吸收较重，则末端基牙应该采用哪一种卡环（）
A.三臂卡环
B.RPI卡环
C.联合卡环
D.间隙卡环
E.对半卡环
题型：单项选择题 共用题干题
1. Great changes _______(take) place in our country in the past thirty years.
2. Peter prefers to stay at home watching TV rather than _______(go) there alone.
3. Now that the headmaster _______(approve) the plan, we can carry it out now.
4. In some countries, missing a bus means _______(wait) for another half an hour.
5. _______(chat) on line took him a lot of time, which led to his failure in the exam.
6. The law requires that everyone _______(have) his car checked at least once a year.
7. _______(achieve) success, you should concentrate on what you are doing.
8. It’s a pity that I missed _______(see) the film which was on at the cinema last 
week.
9. When I entered, the teacher, along with her lovely students, _______(dance) to the music.
10. Susan couldn’t tolerate _______(work) for twelve hours a day and decided to change her job.