The phrase 'has been achieved before' is correct and can be used in written English.
You can use the phrase when you want to emphasize that you have achieved something before. For example: "I have run a marathon before, so I know that this goal has been achieved before."
Such an ambitious scheme has been achieved before, after the Vietnam war, when western countries welcomed 1.3 million refugees from Indochina.
"I always assumed that if you do your job, especially if you achieve what never has been achieved before, that would be fine," says Conway, referring to his success at turning around America West after its 1991 bankruptcy.
"We are going to build our system and our mission around what has been achieved before.
It also highlights how mass-resettlement is not a quixotic policy; it has been achieved before in the aftermath of a bloody war – and could be achieved again.
The system combines a substrate with a biocatalyst in free solution, incubates the two components until full conversion to product has been achieved, before extracting the product.
When the mix of fuel and air is ignited, the resulting gas reaches an extraordinary temperature of 2,200C - a higher level than has been achieved before - which is meant to maximise the output of each drop of fuel.
"As soon as I heard the tremendous expansion of what musical sound could be, it triggered musical ideas, gave me access to a whole new world of sound that could never have been achieved before," said Mr. Deutsch, 72, who retired as chairman of the music department at Hofstra University in 2001 and continues to teach there as an adjunct.
Similarly, the sort of body mapping, best illustrated by the queen of prints Mary Katrantzou, could not have been achieved before the advent of digital design.
And it is not just unusual but unprecedented for the stated primary aims of such a war (in this case, to prevent Iraq from obtaining weapons of mass destruction and from aiding terrorist attacks on the American homeland) to have been achieved before a shot was fired, forcing the war's advocates to scramble for new ones.
Such "spin injection" had been achieved before in more exotic semiconductors, such as gallium arsenide and indium arsenide.
Li's site lists his "many important accomplishments" and notes: "All these have been achieved before the age of forty".
