) Rewrite these sentences making them positive. 1 Robert didn't wait for his friends this morning. 2. They didn't listen to music at 11 p.m. last night. 3. My mother didn't clean the kitchen yesterday. The students didn't learn Japanese last year. Mr. Smith didn't arrive home before dinner Her aunt didn't cook the dinner on Tuesday.

With the development of civilization man's interference in nature grows up. it leads to different negative factors are: the pollution of water, air, soil and the destruction of the ozone layer. this problem must be solved if we want to preserve life on our planet. this problem is global problem that's why all countries of the world, all people, young and old, must take an active part in the protection of natural resources. factories and plants must have purification systems to preserve the purity of water, air and soil. we must take care of plants, trees, animals, birds and fishes, especially of those that are dying out. we also have a red book where rare and dying out plants, birds, animals are registered. though the role of people in the solution of ecological problems has greatly increased, we can't say that we are doing all in our power, to stop harmful processes in preserving the environment. the following radical measures must be taken: 1.the replanting of trees that have been cut down; 2.nuclear tests should be stopped; 3.purification systems must be installed at plants and factories; 4.natural resources should be used more rationally; 5.rare and dying out birds, animals and plants should be protected; 6.precaution measures should be taken against the destruction of the ozone layer.

ответ:Утвердительные :

1.I must go to school.(я должен идти в школу)

2. I must do gardening( я должен заниматься садоводством )

3. I must take care of my animals . (Я должен заботиться о животных)

Отрицательные :

1. I mustn't have cats .(я не должен иметь кошек)

2. He mustn't go for a walk.he is ill (он не должен идти на прогулку . Он болеет)

3.my sister mustn't drive. She ıs only ten years old ! (Моя сестра не может водить . Ей только 10 лет!)

После модального глагола must ,частица to не ставится!

Объяснение:

∫∅х