单选题
One of the most mysterious archaeological spectacles in the world is the immense complex of geometrical symbols, giant ground-drawings of birds and animals, and hundreds of long, ruler-straight lines, some right across mountains, which stretch over 1,200 square miles of the Peruvian tablelands, at Nazca.
Nazea was first revealed to modern eyes in 1926 when three explorers looked down on the desert from a hillside at dusk and briefly saw a Nazca line highlighted by the rays of the sun. But it was not until the Peruvian airforce took aerial photographs in the 1940s that the full magnificence of the panorama was apparent. Hundreds of what looked like landing strips for aircraft were revealed. There were eighteen bird-like drawings, up to 400 feet long; four-sided figures with two lines parallel; and long needle-like triangles which ran for miles. Among the many abstract patterns were a giant spider, a monkey, a shark, all drawn on the ground on a huge scale.
The scale is monumental, but from the ground almost invisible and totally incomprehensible. The amazing fact about Nazca, created more than 1,500 years ago, is that it can only be appreciated if seen from the air. Many, therefore, regarded it as a prehistoric landing ground for visitors from outer space, but Jim Woodman, an American explorer, who was long fascinated by the mystery of Nazca, had a different opinion. He believed that Nazca only made sense if the people who had designed and made these vast drawings on the ground could actually see them, and that led him to the theory that the ancient Peruvians had somehow learned to fly, as only from above could they really see the extent of their handiwork. With this theory in mind, he researched into ancient Peruvian legends about flight and came to the conclusion that the only feasible answer was a hot-air balloon.
To prove his theory, Woodman would have to make such a thing using the same fabrics and fibers that would have been available to the men of Nazca at the time. He started by gathering information from ancient paintings, legends, books and archaeological sites. After many attempts, Woodman built a balloon-type airship. It took him into the air, letting him have the sensation he had never had from viewing the same ground that he had seen many times. His flight was a modern demonstration of an ancient possibility.

单选题 One of the "most mysterious archaeological spectacles in the world" is ______.

单选题 Nazca was discovered in 1926 when ______.

单选题 The "landing strips for aircraft" (in Paragraph 2) were really ______.

单选题 Jim Woodman felt sure that ______.

单选题 Woodman"s flight proved ______.