Huge squares, great buildings and countless treasure — this year, the world’s largest   wooden palace, the Forbidden City, is 600 years old! It lived t【小题1】 fires and wars. But it still stands at the heart of Beijing today. And it never f【小题2】 to catch its visitors’ eyes.

Have you ever wondered who made this marvel(奇迹)?

In 1406, when the third Ming Emperor Yongle d【小题3】 to move the country’s capital from Nanjing to Beijing, he started to build a palace at the heart of Beijing. His vision(愿景) was big. It took a million workers 14 years to finish it.

People sent materials from all over China to Beijing. Nanmu, the rarest of all Chinese woods, was used to make huge wooden pillars(柱子). People can only find it deep in those warm forests over 1,800 km away from Beijing. Workers had to float(漂浮) the wood on rivers all the way n【小题4】 to Beijing.

Stones were also transported to the palace. The h【小题5】 stone in the Forbidden City is 250 tons. It was found 80 km west of Beijing. Because of its w【小题6】, people could only move it during winter. They poured water onto the road to create ice. Then t【小题7】of workers in front kept pulling the stone on the ice to the palace.

The project even changed the local landscape(地貌). While building a river around the palace, workers dug up soil and piled it on a hill behind the Forbidden City. That’s e【小题8】 where Jingshan came from.

The palace also holds many stories about ancient Chinese c【小题9】 that still stays with us today. For example, there are mythical(神话的) animals s【小题10】 on the palace’s roofs. The number of animals shows the status of a building — the more animals there are, the greater the building is.

Have you ever visited Longmen Grottoes（龙门石窟）or Yungang Grottoes? Around 1, 800 years ago, Chinese artists 【小题1】（create）grotto statues（雕像）in mountains. Over the years, these statues have been through earthquakes, floods and wars. Now 【小题2】 the 21st century, however, they are facing much 【小题3】（big）problems. Too many tourists go to visit those grottoes every year and this 【小题4】（certain）does harm to the grotto statues. Do you know how?

According to a study, the CO₂ that visitors breathe out has made the air more acidic（酸性的）. Also, visitors bring in microorganisms（微生物）. Because of these, the grotto statues are in a 【小题5】（danger）situation.

Behaving（表现）badly can cause harm to the grotto statues as well. Too many visitors touch the grotto statues and cause 【小题6】（they）surfaces to change color.

When we visit the grottoes, we can often see a sign saying, “No Flash（闪光灯）!” or “No Photos!”. This is 【小题7】 the strong light can be bad for the statues, especially those with color. The light can make it easy for them to lose their color.

【小题8】（protect）those ancient cultural treasures, recently China has asked the workers who take care of those grottoes to control 【小题9】 number of visitors. And tourists are encouraged to book（预定）【小题10】（ticket）on the Internet and stay away from busy hours when visiting.