句型转换。按要求完成下列句子，每空一词。

1. It is necessary to do eye exercises between classes. (改为同义句)

    _____ eye exercises between classes _____ necessary.

2. Playing sports right after meals is bad for our health. (加good 变为选择疑问句)

    _____ playing sports right after meals bad _____ _____ for your health?

3. You may watch TV for 2 hours tonight. (改为一般疑问句并作否定回答)

    _____ _____ watch TV for 2 hours tonight?

    _____ , you _____ .

4. I usually sleep 7 hours every night. (对画线部分提问)

    _____ _____ do you usually sleep every night?

5. Don't walk on the lawn. (用must改写句子,其句意不变)

    You _____ _____ on the lawn.