. —Why didn’t you response to their greeting?—Sorry. I they to me.A. don’t realize; are w

问题补充：

. —Why didn’t you response to their greeting?

—Sorry. I they to me.

A. don’t realize; are waving

B. don’t realize; were waving

C. didn’t realize; were waving

D. didn’t realize; are waving

答案：

A. don’t realize; are waving

B. don’t realize; were waving

(答案→)C. didn’t realize; were waving

D. didn’t realize; are waving

解析：这题考查时态，句意是：--你为什么不回答他们的问候？--对不起，我没意识到他们在向我挥手。所以是过去没意识到，另外主句是过去时，从句也是相应的过去时。选C。