Сделайте предложения вопросительными и отрицательными 1.We have just sent a telegram 2.They have already seen that exhibition

1. We have just sent a telegram. Have we just sent a telegram? We have not just sent a telegram. 2. They have already seen that exhibition. Have they already seen that exhibition? They have not seen that exhibition yet. 3. We have known him for more than ten years. Have we known him for more than ten years? We have not known him for more than ten years. 4. My friend has already left for Moscow. Has my friend already left for Moscow? My friend has not left for Moscow yet.