Объясните, почему данные предложения написаны правильно: 1. interesting news _is_ that songbirds and parrots can learn human speech. 2. these cases prove that the thames estuary can become an important area for the _conservation_ of the north sea mammals. 3. this engineer came up with idea after _having noticed_ a mother pushing a child in a pushchair. 4. some games _became_ common features of court culture. they were given as expensive gifts. 5. swans are _creations_ of myth and the general belief is that they mate with their partners for life, bow gracefully to each other and sing when they die. 6. some birds learn to communicate vocally by learning from others. birds always_have been taught_ their language by parents and dominant birds in the flock.
2. These cases prove that the Thames Estuary can become an important area for the _conservation_ ( существительное в единственном числе) of the North Sea mammals.
3. This engineer came up with idea after _having noticed_ ( перфектный герундий в действительном залоге (Perfect Gerund Active) показывает действие, которое произошло раньше действия, выраженного сказуемым предложения) a mother pushing a child in a pushchair.
4. Some games _became_ ( Past Simple Active -констатация факта) common features of court culture. They were given as expensive gifts.
5. Swans are _creations_( глагол are связуется с множественным числом имён существительных) of myth and the general belief is that they mate with their partners for life, bow gracefully to each other and sing when they die.
6. Some birds learn to communicate vocally by learning from others. Birds always_have been taught_( Present Perfect Passive- страдательный залог,действие происходило над птицами и результат этого действия имеет отношение к настоящему) their language by parents and dominant birds in the flock.