<image>In the figure, the time and height records of two airplanes made by the model airplane team during a flight are shown.

(1) Plane A flew for ______ seconds, and plane B flew for ______ seconds.
(2) According to the graph, at the 10th second after takeoff, the height of plane B is ______ meters; the two planes were at the same height at the ______ second after takeoff; approximately at the ______ second after takeoff, the height difference between the two planes was the greatest.
(3) From the 15th second to the 20th second after takeoff, the flying state of plane B was ______.