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)