—Hi Susan where were you at lunch time？I a seat for you in the coffee shop.—Oh sorry t

问题补充：

—Hi, Susan, where were you at lunch time？I a seat for you in the coffee shop.

—Oh, sorry to miss you.My political science class ran longer than usual.

A. am saving

B. was saving

C. had saved

D. have saved

答案：

A. am saving

(答案→)B. was saving

C. had saved

D. have saved

解析：考查时态。根据语境判断，吃饭是过去发生的事情，强调在吃饭的过程中“一直为对方留着位子”，所以应该用过去进行时。