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. Ifyou add a word, put an insertion mark (Λ) in the right place and write the missing word in the corresponding blank on your answer sheet. Ifyou delete a word, cross it and put a slash (/) in the corresponding blank on your answer sheet. Ifyou 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.
问答题
（21）
【正确答案】Why → When
【答案解析】
问答题
（22）
【正确答案】in → on
【答案解析】
问答题
（23）
【正确答案】afford → afford to
【答案解析】
问答题
（24）
【正确答案】at → on
【答案解析】
问答题
（25）
【正确答案】increasing → increasingly
【答案解析】
问答题
（26）
【正确答案】interesting → interested
【答案解析】
问答题
（27）
【正确答案】unavailable → available
【答案解析】
问答题
（28）
【正确答案】which → to which
【答案解析】
问答题
（29）
【正确答案】allows → allow
【答案解析】
问答题
（30）
【正确答案】which → over which
【答案解析】