完成对话。 Millie: Hi, Sandy, 1 you _____ (start) your history project yet? Sandy: Yes. I 2 (look) on the Internet to get some ideas, but I 3 (not write) the report yet. Millie: What 4 you _____ (decide) to write about? Sandy: I want to write about Tianjin. 5 you _____ (be) there? Millie: Yes. I 6 (go) there with my family last year. I think Tianjin 7 (not change) much. Sandy: I think there 8 (be) some changes. I 9 already _____ (learn) a lot about the history of that city.