Although Igor Ivanovich Sikorsky was not the(1) .... of the helicopter. INVENT The (2)....of his contribution to its development is not in doubt. IMPORTANT (3).... thousands of years ago, the Chinese played with APPEAR (4).......

Although Igor Ivanovich Sikorsky was not the(1) .... of the helicopter. INVENT The (2)....of his contribution to its development is not in doubt. IMPORTANT (3).... thousands of years ago, the Chinese played with APPEAR (4).... Toys could fly into the air, and even da Vinci drew plans for a helicopter. WOOD However, at that time, it was (5)..... to build a real one. POSSIBLE Century, science become (6).... advanced enough and Sikorsky was the (7)..... TECHNOLOGY SCIENCE who made the successful helicopter a reality. As a child, Sikorsky had been encouraged by his mother, a doctor, and his father, a (8)...., to view science as a series of connected (9)..... PSYCHOLOGY DISCOVER Today, all modem Hali copter are based on his (10).... designs. REVOLUTION