Question

【题目】—Does your father smoke?

—No , it's two years __________ he smoked.

A. before

B. since

C. after

D. when

Answer 1

【答案】B

【解析】句意：——你爸爸抽烟吗？——不抽烟。他戒烟两年了。根据No可知“抽烟”这个动作早已结束。since从句的谓语是延续性动词时，表明动作早已结束；其次，since从句为一般过去时，其主句为it's或it has been，所以此题选B。