从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
( ) 21. --- Yesterday’s concert was wonderful, wasn’t it?
--- Yes, I have never heard such a ______ one.
A. more exciting B. more excited C. most exciting D. most excited
( ) 22. --- Don’t put the waste on the ground.
--- Oh, sorry. I ______ the dustbin just over there.
A. hadn’t seen B. can’t see C. didn’t see D. haven’t seen
