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

1 inventor2 importance3 appeared4 wooden5 impossible 6 technologically 7 scientistPsychologist9 discoveries10 revolutional