. —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
网友回答
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。