What are the four general theories Qian Xi said about the origin of tourism?

As for the origin of tourism, there are generally four theories stated by Qian Xi:

1. Travel as a social behavior has existed since ancient times. China is one of the ancient civilizations in the world. First, the rise of travel activities is also at the forefront of the world. China has it as early as the 22nd century BC.

2. As early as the Yin and Zhou dynasties, people had begun to pay attention to the types of travel. In the Book of Changes, a hexagram that specifically talks about traveling merchants is called the Travel hexagram. The word "lv" is used for business travel. Firstly, "lv" originally means walking. Secondly, "trip" was often used as a hut by the ancients. The word "lv" connected with the word "lu" became the specific name for commercial tourism at that time.

3. The word tourism was first seen in the Six Dynasties and the Qi and Liang Dynasties. Shen Yue sadly went on a trip to charm the spring of the year. Traveling for the main purpose is different from other utilitarian travels.

4. The concept of entertainment travel has changed. Before World War II, only the wealthy, free and well-educated people in society traveled abroad and were content to appreciate foreign scenery and works of art.