Question

Boeing ____ this week that it ____ successfully ____ a manned airplane powered _____ hydrogen fuel cells. Escolha uma opção: a. announced / has / flown / by b. have announced / has / flown / on c. announced / had / flown / on d. announced / has / flown / on e. has announced / had / flown / by

Answer 1

Boeing has announced this week (present perfect tense) that it had successfully flown (past perfect tense) a manned airplane powered by hydrogen fuel cells. (o verbo “power” está em passive voice, portanto a preposição que segue é by)

Então, alternativa E) é a correta!