1, there are more tourists when men are near, and fewer people when they are far away. The transcendent world outlook is often far from danger, but people are rare, and those who have no will cannot come.

2. People who are ambitious and don't stop, but not strong enough, can't get there. Have ambition and strength, but don't be lazy. As for that kind of gloom and confusion, nothing can match it or reach it.

3. Things are not visible or audible, but whether they exist or not.