Many small roads do not have painted markings along theiredges. Clear edge markings would make iteasier for drivers to see upcoming curves and to judge the car's position onthe road, particularly when visibility is poor, and would therefore seem to bea useful contribution to road safety. However, after Greatwater County painted edge markings on all itsnarrow, winding roads, the annual accident rate along those roads actuallyincreased slightly.
Which of the following, if true, most helps to explainthe increase in accident rate?
(A) Greatwater County has an unusually high proportion ofnarrow, winding roads.
(B) In bad weather it can be nearly as difficult fordrivers to see the road as it is at night.
(C) Prior to the painting of the edge markings,Greatwater County's narrow, winding roads already had a somewhat higheraccident rate than other Greatwater County roads.
(D) Many of the accidents on narrow, winding roadsinvolve a single vehicle veering off the road, rather than the collision of twovehicles.
(E) After the markings were painted on the roads, manydrivers who had gone out of their way to avoid driving on those roads at nightno longer did so.
B: 谓语动词canbe as difficult, 没有变化;
D: 谓语动词是involve, 较难判断是否是变化的。许多事故都是涉及到单个车翻下路，而不是两车碰撞。那很有可能原来的路上的情况也是这样的。所以不能解释为什么事故率上升;
E: no longer didso表明了一种变化，并且时间也符合(after….)。以前不在这条路上开车的driver, 现在开始在这条路上开车,所以事故率有了上升。