I can never forget the days _____ we worked together and the days _____ we spent together.A. when; which B. which; when C. what; that D when; when
31. The chair looks rather hard,but in fact it is very comfortable to________.
30. Wang Tao was made_______ the dishes for a week as a punishment.
29. When I handed the report to John,he said that George was the person______.
28.Although _____ to stop, he kept on working.
27.The question _______ at present has something important to do with our nature.