At the present time the significant changes have been occuring and they are not always positive. Ozone layer protects the earth’s surface from the sun's ultraviolet rays, debilitating the organism's ability to withstand the diseases. It is broken by chlorofluorocarbon, utilizing in aerosol production, in the manufacture of materials for the sterilization of medical equipment and etc. The greenhouse effect and acid rains are the result of burning of the fossil fuels, disposable by different sources. Mass cutting down of forests leads to disruption of the process of rotation the oxygen and carbon in the biosphere. Ecological balance is disrupted also by plenty of disposable garbage and water pollution by harmful substances.
Every year a lot of species of plants and animals have been destroying , forest cover has been exterminating, mineral reserves have been decreasing, the world ocean has been becoming depleted. These losses are incommensurable.
The global environmental crisis may turn into a catastrophe for the planet in the future. If mankind doesn’t change the way of consumption the natural resources, there will begin famine, deficit of clean water and outburst natural disasters. The environmental crisis is overcame by means of ecological education of all stratum of the society, creation of effective nature conservation legislation, implementation the good scientific and technical solutions, applying the conservation ecology.
1. Tom wasn't /weren't at school last week.
2. It was / were cold yesterday.
3. My parents wasn't/ weren't in Italy last year.
4. Sally was / were in the country at the weekend.
5. Sarah wasn't / weren't happy yesterday.
6. They was / were late for school last Tuesday.
7. Dave wasn't/ weren't tired yesterday.
8. Ted and Jill was / were at the theatre last night.
Правило очень простое:
Когда действие выполняет один человек или предмет, используй WAS,
а если действие выполняют несколько людей или предметов, то нужно использовать форму WERE.