＿＿＿＿＿＿ for the free tickets, I would not have gone to the films so often.

A．If it is not

B．Where it not

C．Had it not been

D．If they were not

正中关系又称（）

A.牙位

B.肌位

C.位

D.姿势位

E.后退接触位