4. There is a great celebration for girls every year on March 3rd. (The corrected sentence: There is a great celebration for girls every year on March 3rd.)

5. What I like about festivals is that they showcase the values of different cultures. (The corrected sentence: What I like about festivals is that they showcase the values of different cultures.)

6. Hoi An is an old city with many interesting places. (The corrected sentence: Hoi An is an old city with many interesting places.)

7. The preparation for the flu festival is done by my group. (The corrected sentence: The preparation for the flu festival is done by my group.)