(2012年重庆联合诊断性考试)It is rather difficult to make friends with him,but his friendship,________,is more true than any other's.
31. ________was difficult to save the places and buildings _____destroying their old beauty.
30. If we had followed his suggestion, we could have done the work better with _______money and ______people.
29. I won’t listen to the new CD unless I ______my homework.
28. Think after you read ____.
27. Great changes _______in our city in the past twenty years.