All of them have told Ann about it.(改为被动语态)
Ann()()()()it by all of them
What's Tom's favorite subject?Could you tell me?(合并为复合句)
Could you tell me()Tom's()()()?
There are more students in Class 5 than in Class 6.(改为同义句)
The()of studengs in Class 5 is ()()()in Class 6