Helicopters: voz passiva no passado (B1)
A helicopter can do something no aeroplane can: it can stay in the air above a single point. The first practical machine ___ in the late 1930s, and since then helicopters have saved thousands of lives. They rescue climbers from mountains, carry patients to hospital and bring food to villages after floods. However, they are noisy, expensive and difficult to fly, because the pilot must control several movements at the same time. In cities, many people complain about the constant noise of helicopters used by television companies and by rich passengers avoiding traffic.
Fonte: English for ALL (texto original).
Assinale a alternativa que completa corretamente a lacuna do texto.
- A) was build
- B) were built
- C) has built
- D) was built
- E) is building