1. The cat is very playful. It is playing with the wool.
-> The cat which is playing with the wool is very playful.
2. People say that he drives carefully.
-> He is said to drive carefully.
3. Lan is the best student in your class, isn’t she?
-> No one in your class is as good as Lan, aren't they?
4. Thuy was exhausted; however, she managed to finish her work on time.
-> Exhausted was Thuy; however she managed to finish her work on time.
5. The music was so exciting that we danced all night.
-> It was such exciting music that we danced all night.