The phrase "have extended over" is grammatically correct and can be used in written English.
Example: "The effects of climate change have extended over the entire globe, impacting both human populations and natural habitats."
It could have been a town of a few hundred or more people, and might have extended over an area of as much as 10 acres.
After 624 the western Slavs rose against the Avars under the leadership of the Frankish merchant Samo, whose short-lived rule may also have extended over the territories of the eastern Alps.
It is clear that the Sami were already present north of the Gulf of Finland prior to the arrival of the first Baltic-Finnic tribes, and from there they may have extended over much of the Scandinavian Peninsula.
And because the primaries will have extended over such a long period, by August and the Convention some of the voters will have changed their preference as a result of the many revelations, faux pas and new bits of evidence that have intervened since they voted.
He considered that conditions similar to those found today may once have extended over the large submerged area now represented by the shallow banks, with scattered mangrove keys, which stretch towards the Isla de la Juventud and perhaps eastward along the southern Cuban coast.
In some instances, co-existence must have extended over centuries, indicating that these populations have reached accommodation.
WARREN--William D. To a friendship that has extended over many years.
The search for long lost relatives has extended over decades and still goes on.
In Burlington County, N.J., officials reported that a major fire in the Pinelands had extended over 1,000 acres.
The movie's influence has extended over 60 years to take in Cronenberg's homage, A History of Violence.
One of Mr. Cavell's philosophical projects, which has extended over three decades, has been to see the world through the scrim of a mere dozen films.
