. Напишите следующие предложения в вопросительной и отрицательной формах:Образец: They are working. Are they working?

 1. He is looking for the book which he lost. Is he looking for the book which he lost? He isn\'t looking         for the book which he lost.

2. The sky is getting very dark. Is the sky getting very dark? The sky isn\'t getting very dark.

3. They are laughing at what you said. Are they laughing at what you said? They aren\'t laughing at          what you said.