Used to describe an action that was ongoing continuously in the past up until another past event interrupted it.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Gates and Vulcan brought in Asner because of his work with the Global Airborne Observatory that had been mapping reefs in Hawaii at the time.
From Seattle Times ● Sep. 8, 2021
Johnson, who had been mapping the KT layer in Hell Creek, said that his research indicated that Tanis was at least forty-five feet below the KT boundary and perhaps a hundred thousand years older.
From The New Yorker ● Mar. 29, 2019
In the fulness of the new joy which had suddenly transformed his life, the son went on to talk of the plans that he had been mapping out for the future.
From Chinese Folk-Lore Tales by J. (John) Macgowan
On the other hand, the Niccola had been mapping, which was bound to attract attention.
From The Aliens by H. R. van Dongen
On entering the hotel we were greeted by an old Grand Canyon friend, a civil engineer named Duff, who with a crew of men had been mapping the mountains near Whirlpool Canyon.
From Through the Grand Canyon from Wyoming to Mexico by E. L. (Ellsworth Leonardson) Kolb
