句型转换。
1. John answered all the questions. (改为被动语态)
All the questions _____ _ _____ John.
2. They are too tired to continue working. (改为同义句)
They are _____ _____ _____ they can't continue working.
3. His brother joined the army when he was 22. (改为同义句)
His brother joined the army _____ _____ _____ _____ 22.
4. What a tall tree this is! (用how改写)
_____ _____ _____ tree this is!
5. Some people believe that Chinese is difficult to learn. (改为同义句)
It _____ _____ _____ Chinese is difficult to learn.
