—Did you have to take a bus to school?
—Yes, I ______.[ ]
A. had
B. was
C. did
答案:C
一个梯形的上、下底之和是24厘米,高是12厘米,这个梯形的面积是( )平方厘米。
全口义齿戴牙后,下颌髁突明显向后上移位,原因为()
A.正中错位
B.垂直距离过低
C.垂直距离过高
D.义齿咬合关系不佳
E.义齿变形