牙齿唇舌向倾斜度最小的牙是（）。
A.A67
B.A1
C.C67
D.上下前磨牙
E.C2
参考答案：E
板块发生张裂运动时，地表会发生的现象是（ ）
①断裂陷落 ②地表隆起 ③形成高大山脉 ④形成新的海洋．
A．①②
B．②③
C．③④
D．①④
Of the 300 passengers ____ the plane, 245 were killed and 55 were seriously injured. [ ]
A. abroad
B. aboard
C. board
D. broad
