【题目】Since the new prohibition of drunk driving_____, the number of accidents in the area has fallen sharply.
A. has been introduced B. introduced
C. was introduced D. has introduced
在线课程【答案】 C
【解析】
试题分析：考察时态。这是一个Since引导的时间状语从句。Since多用在表示过去的时态，意思是自从。因为该醉驾禁令是被引发布，所以要用被动语态。该句意思为：自从新的醉驾禁令发布，该区域的事故数锐减。故选C