决定基牙观测线位置的是（）

A.牙长轴

B.外形高点线

C.导线

D.支点线

E.就位道

Passage Four

Which of the following is NOT a reason that many motorway accidents are categorized under headings other than sleepiness

A．The Transport and Road Research Laboratory finds the cause as "perceptual errors".

B．Drivers are unwilling to admit to "falling asleep" for fear of being dismissed.

C．Few investigators inquire further to discover the actual reasons hidden behind.

D．Insurance companies are reluctant to pay insurance for drivers’ sleepiness.