According to the query of Baidu question bank, libraries and stacks with more than 6.5438+0 million books belong to a class of high-rise civil buildings. A. correct; B. mistakes; Correct answer: b; Therefore, libraries and stacks with more than 6,543,800 copies do not belong to a class of high-rise civil buildings.

A class of high-rise civil buildings are classified according to building height, number of floors used and total floor area. A class of high-rise buildings with a height of more than 50 meters (inclusive) and a height of more than 19 and 19, with a fire resistance rating of 1, are classified as Grade I. "