wuyazi-Police installed traffic camerasand 闯红灯reduced inthe year, 答案应该是police did not consider there could befluctuation year to year.
题目是police装了摄像头之后,观察到闯红灯的现象减少了,所以police觉得装摄像头很有用。问flaw
答案有
A.police did not consider there could be fluctuation year to year.
B.其他没装摄像头的地方可能闯红灯的现象变多了,police欠考虑
C.到底是装了camera使闯红灯变少了?还是闯红灯本来就变少了,所以用camera观察到的闯红灯现象变少了?(即无法确定因果)