Read the following passage about and mark the letter A, B, C, D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

Leonardo da Vinci was born on April 15, 1452 in Vinci, Italy. He was the illegitimate son of Ser Piero, a Florentine notary and landlord, but lived on the estate and was treated as an illegitimate son.

In 1483, Leonardo da Vinci drew the first model of helicopter. It did not look very much like our modern day "copter," but the idea of what it could do was about the same. Leonardo was an artist and sculptor. He was very interested in motion and movement and tried to show it in his art. In order to show movement, he found it helpful to study the way things moved.

One subject he liked to study was birds and how they flew. He spent many hours watching the birds and examining the structure of their wings. He noticed how they cupped air with their wings and how the feathers helped hold the air. Through these studies, Leonardo began to understand how birds were able to fly

Like many other men, Leonardo began to dream of the day when people would be able to fly. He designed a machine that used all the things he had learned about flight, and thus became the first model of a helicopter.

Poor Leonardo had only one problem, however. He had no way to give the necessary speed to his invention. You see, motors had not yet been invented and speed was an important part of the flying process. It would be another four hundred years before the engine was invented and another fifty years before it was put to the test in an airplane.

Leonardo's dream of a helicopter finally came to pass in 1936. The Italian painter, sculptor, architect, engineer, and scientist, Leonardo died on May 2, 1519, and was buried in the cloister of San Fiorentino in Amboise.

(Adapted from: Overview of Traditional Festival - Vietnam, Country and People)

The following sentence would best complete which paragraph? "Since then people have been living out Leonardo's dream of flying."