I think the shop is closed _____ this time of day.[ ]
A. in
B. on
C. at
D. for
答案:C
人工牙排列要有平衡的主要原因()
A.使接触面积广
B.使咀嚼效率高
C.使义齿稳定
D.使义齿看起来美观
E.纠正偏侧咀嚼习惯