The ruins of a Maya city have been discovered in Guatemala with the help of the

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    The ruins of a Maya city have been discovered in Guatemala with the help of the remote sensing technique LiDAR. This lost city envelops sites like Tikal, Holmul, and Witzna, but shows that these famous areas are a small part of this lost urban network.
    Hidden under the jungles of the Maya Biosphere Reserve site, more than 60,000 human-made features — homes, canals, highways, and more — have been identified in aerial (从飞机上的)images collected by some international researchers headed by the PAGUNAM Foundation, a Maya cultural and natural heritage organization. Those have experts rethinking the outlines and complexity of the Maya Empire.
    These ancient peoples obviously created these imaginative cultures based on their known relics (遗迹), but the new research has suggested that the size of this lost society is far beyond what experts imagined. The findings will be explored in a one-hour documentary called "Lost Treasures of the Maya Snake Kings", to be broadcast on the National Geographic Channel.
    This breakthrough was possible thanks to LiDAR sensors, which can survey lands in 3D by bouncing pulses off the ground from unmanned air vehicles and others. LiDAR is exceptionally useful for detecting archeological(考古的)sites, as it gets through jungles and other features that hold up exploration on the ground. The technique has made many discoveries become a reality in recent years. For instance, major finds at Angkor, Cambodia and Caracol, Belize can explain what it did. The final goal is to survey Guatemala's lowlands with it.
    "There are entire cities we didn't know about now showing up in the survey data," Francisco Estrada-Belli, one of the lead archeologists on the project, said in Nat Geo's coming documentary. "There are 20,000 square kilometres more to be explored and there are going to be hundreds of cities about the mysterious people who built this urban network there that we don't know about，and we will push back the frontiers with the technology," he added.
（1）What does the underlined word "Those" in paragraph 2 refer to?            
A.Jungles.
B.Human-made features.
C.Researchers.
D.Aerial images.
（2）What does the underlined word "Those" in paragraph 2 refer to?            
A.Jungles.
B.Human-made features.
C.Researchers.
D.Aerial images.
（3）What does the author want to convey in paragraph 4?            
A.The working principle of LiDAR sensors.
B.The process of researching Maya civilization.
C.Great importance of Guatemalans lowlands.
D.LiDAR's contribution to discovering the relics.
（4）What does the author want to convey in paragraph 4?            
A.The working principle of LiDAR sensors.
B.The process of researching Maya civilization.
C.Great importance of Guatemalans lowlands.
D.LiDAR's contribution to discovering the relics.
（5）Which words can best describe the lost Maya city?            
A.Small and hidden.
B.Famous and high-tech.
C.Vast and complex.
D.Fully-explored and imaginative.
（6）Which words can best describe the lost Maya city?            
A.Small and hidden.
B.Famous and high-tech.
C.Vast and complex.
D.Fully-explored and imaginative.
（7）What will the archeologists do next?            
A.Continue to explore the unknown.
B.Upgrade the LiDAR technology.
C.Study the documentary carefully.
D.Build a massive urban network,
（8）What will the archeologists do next?            
A.Continue to explore the unknown.
B.Upgrade the LiDAR technology.
C.Study the documentary carefully.
D.Build a massive urban network,

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