Dolphins: discurso indireto (B2)
Bottlenose dolphins in Laguna, in southern Brazil, have cooperated with local fishermen for generations, driving mullet towards the nets and signalling the moment to cast with a distinctive dive. The behaviour is learned, not instinctive, and it passes from mother to calf on both sides of the partnership. Researchers who study the population have built an acoustic library of individual whistles, each of which functions rather like a name. At a public seminar in Florianópolis, a journalist asked the team ___, and the answer surprised the audience: eleven years of intermittent recording, most of it done from small boats in poor weather. The scientists added that the tradition is now fragile, because fewer young fishermen learn it and boat traffic increasingly interferes with the sounds the animals rely on.
Fonte: English for ALL (texto original).
Assinale a alternativa que completa corretamente a lacuna do texto.
- A) how long the recordings had taken
- B) how long had the recordings taken
- C) how long did the recordings take
- D) how long the recordings did take
- E) how long have the recordings taken