1 . The Maya city of Tikal is famous for its amazing palaces and temples. But something far more ordinary kept Tikal functioning: its water-purifying(净化) system, the earliest known of its kind.
Researchers recently discovered a volcanic mineral that traps microbes(微生物) and heavy metals in Tikal's largest reservoir(水库). Because the material is not found nearby, the finding suggests the presence of a man-made water-purifying device.
The finding denies the long-standing idea that the ancient worlds technological achievements belonged to the Eastern world, like Egypt, and China. The leading scientist of this research, Kenneth Tankersley says, “When talking about purifying water, the Maya were thousands of years ahead.”
Located in the forests of Central America, Tikal, is thought to have been home to more than 45,000 people. They had to struggle against a dry season lasting from November through April. Storing water in reservoirs was a solution, but that water had to be fit to drink, said Kenneth, “Keeping water clean was of great importance.”
A few years ago, the researchers were surprised to find that the largest reservoir, Corriental, had significantly fewer harmful chemicals than the others. “The water quality at Corriental was much higher.”
Somehow the Maya must have been purifying Corriental’s water, the team assumed. “The Maya used gardens as their bathrooms.” Kenneth said, “The water coming into the reservoir would not have been very clean.”
At the bottom of Corriental, scientists found four separate layers(层), each a few centimeters thick, of millimeter-scale “zeolites(沸石)”. This type of volcanic mineral can purify water and is still in widespread use today, Kenneth says, “Just about everything we drink, from bottled water to wine, runs through a zeolite purifying device.”
The Maya wouldn’t have known about the zeolite in rock, but they would have recognized the purifying effects, the researchers suggest. A zeolite-rich rock formation about 30 kilometers northeast of Tikal is the likely source of the material in Corriental reservoir, the team said last month in Scientific Reports. Water at this site “was clear and tasted good.”
1. What did the researchers find?| A．A new material called zeolites. | B．The purifying effects of zeolites. |
| C．An old water-purifying system. | D．High-quality water in Corriental. |
| A．By building the largest reservoir. | B．By using gardens as their bathrooms. |
| C．By getting rid of heavy metals. | D．By spreading four layers of zeolites. |
| A．The Maya drank bottled water. | B．The ancient Maya were very bright. |
| C．The system was created by accident. | D．The zeolites were found in Corriental. |
| A．the original water in Corriental was not clean enough |
| B．water supply in Tikal lasted from November to April |
| C．all ancient technological achievements belonged to the East |
| D．the Maya had a good understanding of the zeolite in rocks |
