Boeing ____ this week that it ____ successfully ____ a manned airplane powered _____ hydrogen fuel cells.
GadgetDesigners Push the Limits of Size, Safety
By Brian X. Chen, August 28, 2008
Just as small, fast-moving mammals replaced lumbering
dinosaurs, pocketable gadgets are evolving to fill niches that
larger, deskbound computers can’t reach. But as they shrink,
these gadgets are faced with problems mammals face, too,
such as efficiently dissipating heat.
The recent example of Apple’s first-generation iPod nanos
causing fires in Japan raises the question of whether
increasingly innovative product designs are impinging on
safety. The nano incident illustrates how risk can increase as
devices decrease in size, says Roger Kay, an analyst at
EndpointTechnologies.
“As [gadgets] get smaller, the tradeoffs become more difficult,
the balance becomes more critical and there’s less room for
error,” Kay said. “I’m not surprised it’s happening to the nano
because that’s the small one. You’re asking it to do a lot in a
very, very small package and that’s pushing the envelope.”
There’s no question that industrial designers’ jobs have
become much more difficult as the industry demands ever
more powerful and smaller gadgets. With paper-thin
subnotebooks, ultrasmall MP3 players, and pinkie finger-
sized Bluetooth headsets becoming increasingly popular, it’s
questionable where exactly designers draw the line between
innovation and safety.
Boeing ____ this week that it ____ successfully ____ a manned airplane powered _____ hydrogen fuel cells.
- A)announced / has / flown / on;
- B)has announced / had / flown / by;
- C)announced / has / flown / by;
- D)have announced / has / flown / on;
- E)announced / had / flown / on.
Resposta:
A alternativa correta é C)
O gabarito correto é a alternativa C) announced / has / flown / by.
A estrutura da frase exige o uso do Simple Past para o verbo principal "announced", pois se refere a um evento específico ("this week") concluído no passado. A forma "has flown" no Present Perfect é correta para indicar uma ação concluída com relevância no presente, mostrando que o voo foi bem-sucedido. A preposição "by" é a adequada para indicar o meio de propulsão ("powered by hydrogen fuel cells"), significando "por meio de" ou "através de".
As outras alternativas contêm erros: A) usa "on" incorretamente; B) emprega "had flown" desnecessariamente no Past Perfect; D) utiliza "have announced" com sujeito singular e "on" incorretamente; E) combina "had flown" sem necessidade com "on".
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