改错题

Directions: This part consists of a short passage. In this passage, there are altogether 10 mistakes, one in each numbered line. You are required to change a word, add a word or delete a word. If you add a word, put an insertion mark (∧) in the right place and write the missing word in the corresponding blank on your answer sheet. If you delete a word, cross it and put a slash (/) in the corresponding blank on your answer sheet. If you change a word, cross it and put your word in the corresponding blank on your answer sheet. Remember to write the correct number beside each blank on the answer sheet. 

填空题 (21)________
填空题 (22)________
填空题 (23)________
填空题 (24)________
填空题 (25)________
填空题 (26)________
填空题 (27)________
填空题 (28)________
填空题 (29)________
填空题 (30)________