.—May I see your ticket please? I think you in my seat.—Oh you’re right. My seat is ups

问题补充：

.

—May I see your ticket, please? I think you in my seat.

—Oh, you’re right. My seat is upstairs. I’m terribly sorry.

A. are sitting

B. sit

C. sat

D. have sat

答案：

(答案→)A. are sitting

B. sit

C. sat

D. have sat

解析：考查时态。句意：我可以看一下你的票吗？我认为你坐了我的座位。结合语境可知后一句描述的是现在正在进行的动作，故用现在进行时态，选D。