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5组文字，将其分别放回文章原有位置，以恢复文章原貌。 Ruining the Ruins Acid rain (酸雨) is
now a familiar problem in the industrialized countries in Europe. Harmful gases
are produced by power stations and cars. They dissolve in rainwater and this
makes acid rain, which damages trees, rivers and streams. Acid
rain is also capable of dissolving some rocks, and buildings made of soft rock,
such as limestone (石灰石), are particularly badly affected. The acid rain attacks
the rock, and so carvings and statues are eroded (受腐蚀) more quickly. (46) According to a report in the New Scientist, acid
rain is being blamed for the rapid decay of ancient ruins in Mexico. The old
limestone buildings in places like Chichen ltza, Tulum and Palenque are wearing
away very quickly indeed. These sites are the remains of the buildings built by
the Mayas between 250 BC and AD 900, and the spectacular ruins of Mayan
civilization are visited by thousands of tourists every year.
But those ruins are in danger of being seriously damaged by pollution. At
many sites the stone has been covered with a layer of black substance.
(47) . Scientists estimate that about one
millimeter of stone is worn away every twelve years. (48) The
acid rain is said to be caused by pollution from oil wells in the Gulf of
Mexico. Car exhaust gases are also a problem. Local volcanic eruptions make the
problem even worse. Nevertheless, with enough money and effort, researchers say
that many of the problems could be solved and the rate of erosion reduced.
(49) . Mexico’s current lack of funds is also
partly due to oil. The country has rich oil fields and a few years ago, when oil
was expensive, Mexico was selling large quantities of oil to the USA and earning
a lot of money. (50) However, the price of oil then dropped,
and Mexico has been left owing enormous sums of money and with not enough income
from oil sales to pay back the loans. So unless the price of oil rises, it is
unlikely that Mexico will be able to afford to clean up the pollution and save
its Mayan ruins from destruction. A At others the painted surfaces
inside temples are lifting and flaking off (剥落) and the stone is being eaten
away. B That is enough to have caused some of the ancient carvings to
become seriously damaged already. C These measures would reduce the
pollution, but would not stop it completely. D The government was
therefore able to borrow huge sums of money from banks around the world,
thinking they would have no problem repaying their debts. E The
problem, however, is not just a European one. F However, the Mexican
government does not have enough money to do the work, and needs to spend what
money it has on the Mexican people.