词形转换（共8小题，计8分）
【小题1】 It is necessary for everyone to brush his ________ after each meal. (tooth)
【小题2】 I have bought a new flat and it’s on the ________floor of the building.(nine)
【小题3】 As middle school students, we should know how to look after________. (us)
【小题4】The student missed the ________tour around Donggao Park. (enjoy)
【小题5】 We received Peter’s _______and went to his birthday party happily. (invite)
【小题6】             (luck), John got back the notebook that he had lost at the cafe.
【小题7】 It was _________for such a little girl to solve this hard problem in ten minutes. (usual)
【小题8】 Make a plan for your future study, and you will ________in the end. (successful)