She had trouble _____ complete sentences. [ ]
A. make
B. making
C. to make
D. made
答案:B
To take photos, you have to ask ________ from the warden(管理员). [ ]
A. permission
B. permit
C. allowance
D. admission
造成义齿塑料基托颜色发白,明显咬合高的原因是()
A.调拌比例不当
B.填塞过早
C.填塞过迟
D.填塞不足
E.热处理升温过快