The scientist began to study the coral reefs eight years ago

The scientist began to study the coral reefs eight years ago 请问what are the major threats to coral reefs? Coral reefs under the ocean are___every colour,every size an I began to study here two years ago 同义句 Beacuse of the pollution,the c_____ coral reefs are dead and the girl began to learn english five years ago the girl___ _ The twins began to live here two years ago.(用现在完成时改写句子) She began to work in the bank two years ago.she is still wor I began to play the piano four years ago,I always remember m the years of study and work began to pay off ,and i knew i w I began to study English at the age of six.Now l am 15 years 现在完成时英文l began to study English three years ago.l ( ) Englis