理想的冠桩直径应为根径的（）
A.1／5
B.1／4
C.1／3
D.1／2
E.2／3
参考答案：C
嵌体制作时，下列有关洞斜面的说法，正确的是（）
A.洞斜面的角度为30°
B.斜面起于釉牙本质界层
C.预备斜面可去除洞缘无基釉，防止釉质折断
D.可增加嵌体的洞缘密合性
E.宽度为1.5mm
WhateVerhe promises, you can't ____ anything. [ ]
A. rely his doing
B. rely on him to do
C. depend his doing
D. advise him to do
