Although Igor Ivanovich Sikorsky was not the(1) .... of the helicopter. INVENT The (2)....of his contribution to its

Although Igor Ivanovich Sikorsky was not the (1) inventor of the helicopter, the (2) importance of his contribution to its development is not in doubt.  (3) Appeared thousands of years ago, the Chinese played with (4) wooden toys could fly into the air, and even da Vinci drew plans for a helicopter. However, at that time, it was (5) impossible  to build a real one.  In the early 20th century, science become (6)technologically advanced enough and Sikorsky was the (7) scientist who made the successful helicopter a reality. As a child, Sikorsky had been encouraged by his mother, a doctor, and his father, a (8) psychologist, to view science as a series of connected (9) discoveries. Today, all modem helicopters are based on his (10) revolutional designs.