问题
选择题
. —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
答案：C
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。