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  • Определите функции глаголов to be, to have, to do:
    1. Air pollution is a very serious problem.
    2. It is known that many cities throughout the world do suffer from air
    3. The problem of pollution and ecology has become the most important one
    for mankind.

  • 1 is глагол-связка,2.is вспом гл в пассиве.present simple passive, do усилительный глагол.3.has вспом гл в present perfect active.