Question

【题目】We have sometimes accidents on this line, but no accidents ______ since last winter. ( )

A.occurB.have occurredC.have been occurringD.are occurring

Answer 1

【答案】B

【解析】

句意：这条线路有时发生事故，但自去年冬天以来没有发生过意外。根据时间，自去年冬天以来可知用现在完成时。故选B。