=>
VI/
1. wish -> wishes
2. was -> were
3. have -> had
4. used to arrange -> used to be arranged
5. how -> how to

IX/
1. In the past, people used to get into the museum without having to buy entrance ticket.
2. I wish people weren't indifferent to each other nowadays.
3. My mother suggested visiting our grandparents and cooking something good to have dinner together.
4. My father said that amusement park would have been open to public before we moved to the new place.
5. It is so excellent of my youngest brother to have won two scholarships from two famous universities in Australia.

VI./

1.  Lỗi sai: wish  -> wishes

2. Lỗi sai : was   -> were

3. Lỗi sai : have  -> had

4. Lỗi sai : thiếu be  -> used to be

5. Lỗi sai : thiếu to  -> how to