句型转换。

1. Jack sends five emails to his friends every day. (对划线部分提问)

    ______ ______ emails ______ Jack ______ to his friends every day?

2. I sometimes play football with my friends after school. (对划线部分提问)

    ______ ______ ______ you ______ football with your friends after school?

3. They go to the park on Sunday. (改为否定句)

    They ______ ______ to the park on Sunday.

4. We often use a computer in our class. (改为一般疑问句)

    ______ you often ______ a computer in your class?

5. My friends usually play computer games at the weekend. (对划线部分提问)

    ______ ______ your friends usually ______ at the weekend?

最容易析出氢气的溶液环境是哪种？