单选题 In 1785, the French aeronaut, P. Blanchard successfully used a parachute to drop a dog in a basket to the ground from a balloon high in the air. In 1793, Blanchard himself used a parachute to jump from a balloon. His first attempt was not successful — he broke his leg. Others made several attempts, some successful, some not, before parachute jumping came to be common and ______