1.This letter haven't been answered by you. 2.This problem will be discussed by them. 4.An earthquake was predicted in China in 1974 by scientists. 6. Something is being biult there by them. 7. This problem is being investigated currently . 8. A labaratory center will be built by the end of the year. 9. The East coast of Australia was discovered by James Cook.
Объяснение:
3 и 5 и так дано в пассиве . А в условии сказано перевести в пассив. а еще можеш не писать автора действий(by someone)
