下列哪种情况适合采用平均倒凹法确定就位道()。
A.后牙游离缺失
B.前牙缺失
C.单侧多数牙缺失
D.前、后牙同时缺失
E.缺牙间隙多,倒凹大
参考答案:E
已知函数y=2y1-y2,y1与x+1成正比例,y2与x成反比例,当x=1时,y=4,当x=2时,y=3,求y与x的函数关系式.
Some radio waves()the surface of the earth because of its().
A.are capable of following / distance
B.can follow / altitude
C.can hardly follow / shape
D.are unable following / angle