小题1:We will turn off the lights for an hour on Earth Day.(对划线部分提问)

________ ________ we turn off the lights for an hour?

小题2: Shall we have a picnic at the weekend? (改为同义句)

________ ________ having a picnic at the weekend?

小题3:“Will you please open the window?” she said to him. (将直接引语改为间接引语)

She ________ him ________ open the window.

小题4:They kept on talking until the teacher came in. (改为同义句)

They didn’t ________ ________ until the teacher came in.

小题5: The new high-speed Hangzhou-Shanghai line started running last year. It cost about 29 billion yuan. (合并为含定语从句的句子)

The new high-speed Hangzhou-Shanghai line ________ ________ about 29 billion yuan started running last year.

若方程x³-6x²-15x+a=0恰有三个实根，则a的取值范围是______．