Have you ever visited Longmen Grottoes（石窟）or Yungang Grottoes? Around 1, 800 years ago, Chinese artists made statues in mountains. Over the years, these statues have gone through earthquakes, floods and wars. Now in the 21st century, however, they are facing an even bigger problem: tourism. Too many tourists go to visit those grottoes every year and this certainly does harm to the grotto statues. How?
Over many centuries, these grotto statues slowly corrode（侵蚀）because of the acidic content （酸性物含量）of air, water and so on. But when they are open to the public, the corrosion process speeds up.
According to a study, the carbon dioxide that visitors breathe out has made the air more acidic. Also, visitors bring in microorganisms（微生物）. Even their body heat can increase the grottoes’ temperature.
Bad behaviour can cause harm to the grotto statues as well. Too many visitors touch the grotto statues and cause their surfaces to change colour.
When we visit the grottoes, we can often see a sign saying, “No Flash!”or “No Photos!” This is because the strong light can be bad for the statues, especially those with colour. The light can easily make them lose colour.
To protect those ancient cultural treasures, recently China has asked the workers who take care of those grottoes not to allow too many visitors to come every day. And to keep a balance between protecting relies and educating the public, some grotto sites have also created their own digital（数字的）museums.
Title: Grotto Statues Are in
| Problems | The grottoes corrode →The carbon dioxide that visitors breathe out, the microorganisms visitors bring in and visitors’ body heat make the grotto environment more acidic. →Tourists behave badly. ●They touch the grotto statues with their hands. ●The strong light of cameras makes the grotto statues lose colour easily. |
| →Control the → |
