Lời giải cho phần IV:
1. Although my mother is old, she often walks 5km before breakfast.
2. No one in the world plays guitar better than Clemens.
3.
-  The car was too expensive to be bought by my parents.
- The car wasn't cheap so that my parents couldn't buy it.
4. The woman with short hair is talking with my sister.
5. If we don't start saving now, we can't take a trip to Malaysia on holiday.
6. The students must wear school uniform every day.