3／4冠轴沟的正确方向是（）
A.与牙体长轴平行
B.与唇面切1／3平行
C.与唇面切2／3平行
D.与唇面平行
E.与舌面平行
参考答案：C
明代官修的地理总志是？（）
We cannot understand a disease ________ we understand the person who has the disease.[ ]
A. unless
B. even though
C. on condition that
D. while
