The phrase 'has been gained over' is correct and usable in written English.
You can use this phrase when discussing something that has been acquired or earned over a period of time. For example, "The team's impressive knowledge has been gained over several years of dedicated practice."
As we meet today in Washington to discuss the United States-Colombia security relationship, we want to take stock of what has been gained over the past decade and commit our two nations to continue this progress.
This experience has been gained over many years.
This article provides an overview of the knowledge of solid-state bioprocessing that has been gained over this time.
Extensive experience in conducting long term cancer bioassays has been gained over the past 50 years of animal testing on drugs, pesticides, industrial chemicals, food additives and consumer products.
The end of the year is a prime time for reflection, not just upon what has been gained over the past 12 months, but, in the case of the individuals profiled as part of our ongoing I Lost Weight feature, what's been lost.
Much knowledge has been gained over the years in our understanding of the mechanisms underlying the difficult interaction between these patients and the machines used to provide them with the ventilatory support they often require for prolonged periods.
Since the new year, a petition against the bill has been gaining over 2,000 names a day; now, with more than 54,000 signatories, the call for changes to the legislation is becoming louder.
The mainstream centre left or social democrats have been gaining over the past three years.
In the ongoing exploitation of tight gas and conventional gas reservoirs, however, experience in using hydraulic fracturing has been gained by pumping over 300 fracs over the last decades, mainly in the federal state of Lower Saxony [4].
Techniques for laparoscopic radical hysterectomy and lymph node dissection were developed in the early 1990s [3, 4] and considerable experience has been gained since with over 1,000 cases reported in literature [5].
We find that salt tolerance has been gained hundreds of times over the history of the angiosperms.
