Changetheformsofthefollowingsentences. 句
题型：句型转换
问题：
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）