شرکت در آزمون آنلاین زبان انگلیسی 1 - زبان انگلیسی 1 | آزمون شماره 13817

……… is a necessary part of the tourism industry but not the only element.

Little children often try to ............................. their parents' attention in different ways.

The wall that covers the northern border of China is known as the Great Wall of China. It stretches almost 5, 500 miles long, and was built to keep out the Mongols from China. The wall has over 7, 000 lookout towers, and the height varies from place to place, averaging around 33 feet tall. It is the longest and largest man-made structure in the world. Moats were made around the wall to help keep people out, and currently it is one of the New Seven Wonders of the World.

The Great Wall of China is a series of buildings made of stone, brick, tamped earth, wood, and other materials, generally built along an east-to-west line across the historical northern borders of China. There have been many different names given to the Great Wall of China. One of the earliest was Chang Cheng, a term which means `long wall(s)`, which appeared in Sima Qian`s Records of the Grand Historian. People would develop their own name for it, like Wan li Chang Cheng, which means the Ten-Thousand-Mile Long Wall. It would evolve several other times, including names like `The Purple Frontier` or `The Earth Dragon`, and eventually in the 19th century it would become known as The Great Wall.

What is the main idea of the passage?