The phrase "already been kept" is correct and usable in written English.
It can be used to indicate that something has been maintained or preserved up to the present time.
Example: "The documents have already been kept in a secure location for safekeeping."
Alternatives: "already stored" or "already maintained".
His mother said what people really meant was that the promise had already been kept.
The oncologist who continued her clinic after news of a family bereavement because her patients had already been kept waiting to see her.
Breivik, 33, has already been kept at Ila for more than a year under its Regime of Particularly High Security, which is the country's strictest regime for prisoners.
Compared by Maugham to a 'youth painted by Bronzino', Searle had already been kept by other older, affluent men.
In the 1980's, the restaurant, in an effort to seem even more clublike than it already was, kept a sign-in book.
Further, since the timing of athletic events arose in the 19th century -- records were already being kept at the first modern Olympics, in Athens, in 1896 -- there are few starker demonstrations of Darwinism than in the evolution of athletic standards.
More than 1 million tons of radiation-laced water is already being kept on-site in an ever-expanding forest of hundreds of hulking steel tanks—and so far, there's no plan to deal with them.
To not expand the section too much, the discussion of the already published findings is kept short and concise.
Only the alternative species nesting with strong bootstrap support within already selected species were kept.
were added and mixed for 3 min. The mixture was added to PEGA resin (already conditioned) and was kept at room temperature for 4 h with gentle shaking.
The rhinoceros was already well accustomed to being kept in captivity.
