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+1 AFractal wrote:The widely accepted big-bang theory holds that the universe began in an explosive instant 10 to 20 billion years ago and has been expanding ever since.
A. that the universe began in an explosive instant 10 to 20 billion years ago and has been expanding
B. that the universe had begun in an explosive instant 10 to 20 billion years ago and had been expanding
C. that the beginning of the universe was an explosive instant 10 to 20 billion years ago that has expanded
D. the beginning of the universe to have been an explosive instant 10 to 20 billion years ago that is expanding
E. the universe to have begun in an explosive instant 10 to 20 billion years ago and has been expanding
I don't understand, why "has expanded" is incorrect and "has been expanding" is correct. As far as I know, these two forms are both Present Perfect:
has expanded --> present perfect simple
has been expanding --> present perfect continuous
Can somebody explain, why the present perfect simple is incorrect here?
thx a lot!
Life is a Test
