Brooklyn is part of Long island.
Correct.
brooklyn is NOT part of li….
Also correct.
Long Island is an island in the U.S. state of New York. Stretching northeast into the Atlantic Ocean, Long Island contains four counties, two of which, (Brooklyn and Queens), are boroughs of New York City,[2] and two of which are mainly suburban (Nassau and Suffolk). In popular usage, “Long Island” often refers only to Nassau and Suffolk counties in order to differentiate them from New York City, although all four counties are on the island and part of the New York metropolitan area.[3]
From Wikipedia