Part 4 bạn làm đúng hết
Riêng câu 6. visited->visiting
Part 5:
1. taking-> should take
2. Even though-> In spite of/ Despite
3. careless-> carelessness
4. is-> were
Part 6: 
1. This is the second time I have visited the Stone Forest.
2. I find it hard to keep pace/up with my brother on walking holidays.
3. It is three years since we last went to Spain.
4. The old house on the plateau that we visited was magnificent.