不良习惯是否引起错牙合畸形，与不良习惯无关的是（）

A.发生历史

B.发生频率

C.加于牙颌上压力的方向

D.加于牙颌上压力的大小

E.每次持续时间

Had your father seen the doctor earlier, he ___.

A．would have died

B．would not have died

C．would not die

D．has not died