用于前后有缺隙孤立的双尖牙或磨牙的是（） ["RPI卡环","回力卡环","联合卡环","对半卡环","杆型卡环"]
有效防止食物嵌塞的是（） ["RPI卡环","回力卡环","联合卡环","对半卡环","杆型卡环"]
减少远中游离端义齿基牙的卡抱力的是（） ["RPI卡环","回力卡环","联合卡环","对半卡环","杆型卡环"]
金属烤瓷冠的切端牙体磨除厚度一般为（） ["0.5mm","1.0mm","1.5mm","2.0mm","3.0mm"]
洞固位形的深度至少为（） ["0.5mm","1.0mm","1.5mm","2.0mm","3.0mm"]
试述《内经》对脏腑经络论述的要点？
