阅读下列短文，从每题所给的A、B、C和D四个选项中，选出最佳选项。
A
Experts using a high-tech laser scanner (激光扫描仪) have discovered thousands of ancient Maya buildings hidden under the thick forests of northern Guatemala, officials said Thursday. Some 60, 000 buildings were found over the past two years in a scan of an area in the northern department of El Peten between Mexico and Belize, said Marcello Canuto, one of the projects’ lead researchers.
These findings are a “breakthrough in Maya archeology(考古),” Canuto said.
The new discoveries in this Central American country include city centers with sidewalks, homes, wide steps, farming facilities and so on, said Canuto, an archaeologist at Tulane University in the United States.
Among the finds was a 30-meter high pyramid (金字塔) that had been earlier recognized as a natural hill in Tikal. Also discovered in Tikal: a series of holes and a 14 kilometer-long wall.
The Maya development reached its height in what is present-day southern Mexico, Guatemala, and parts of Belize, El Salvador and Honduras between 250 and 950 CE. Researchers now believe that the Maya had a population of 10 million, which is “much higher” than previous judgment, Canuto said.
The project depended on a remote (远程的) sensing method known as LiDAR (Light Detection and Ranging). Aircraft with a LiDAR scanner produced 3D maps of the surface by using light in the form of laser linked to a GPS system.
The technology helped researchers discover sites much faster than using traditional archeological methods. “Now it is no longer necessary to cut through the jungle to see what’s under it,” said Canuto.
Details of the research will appear in a documentary to air on February 11 on the National Geographic TV channel, said Minister of Culture and Sports Jose Luis Chea.
21．What did Canuto think of the new discoveries in the past two years?
A．Leading. B．Frightening. C．Annoying. D．Puzzling.
22．Which one is NOT LiDAR’s advantage?
A．It saves time in discovering site.
B．It is more convenient for researchers to work in forest.
C．Explorers have to go deep into the jungle to research.
D．Research can be done at a distance.
23．According to the new discoveries, Maya might have been a nation________.
A．that lay in Africa B．that was less developed
C．whose pyramid was made of a hill D．with a surprisingly large population
24．What is the author’s purpose in writing the text?
A．To inform readers of the new discoveries about Maya.
B．To introduce a new method used to discover Maya buildings.
C．To show Maya development was of great influence.
D．To tell us a new documentary will be launched on TV in Feb.
