组合练七 Ⅰ.阅读理解 A (2021·福州市3月质量检测) The Maya city of Tikal is famous for its amazing palaces and temples.But something far more ordinary kept Tikal functioning:its water-purifying 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 findings suggest the presence of a man-made water-purifying device. The findings deny the long-standing idea that technological achievements of the ancient worlds 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 to 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 garden