Change the forms of the following sentences. 句型转换。
1. The ping-pong balls are twenty dollars.（对划线部分进行提问）
2. I had fun today.（变为一般疑问句）
3. Jenny teaches me to play ping-pong.（变为一般过去时）
4. My favourite sport is soccer.（对划线部分进行提问）
5. I have some books.（变为一般疑问句）
1. How much are the ping-pong balls?
2. Did you have fun today?
3. Jenny taught me to play ping-pong.
4. What is your favourite sport?
5. Do you have any books?