21. At _____ dawn, we got in touch with my cousin, who lives _____ downtown in a small flat.
A. the; a B. The; / C. /; the D. /; /
22. Many colleges in Sichuan decided to ______ the school due to the big earthquake in May, 2008.
A. delaying to open B. delay opening C. delay open D. delaying open
23. They _____ on the programme for almost one week before I joined them, and now we _____ on it as no good results have come out so far.
A. had been working; are still working B. had worked; were still working
C. have been working; have worked D. have worked; are still working
24. When the old man was alive, he _____ sit for hours at the door, waiting for his grandson back from school.
A. might B. must C. got used to D. would
25. Without facts, we cannot form a worthwhile opinion, for we need to have factual knowledge _____ our thinking.
A. which to base B. Which to be based on C. upon which to base D. upon which to be based