人们生活在世界上,离不开衣食住行。古人由于当时的生产力十分低下,生活条件自然是比较原始而简单。原始人穴居,是为了避风雨,防野兽。以后逐渐有了简陋的居处,一般风雨不再构成威胁。但人类要生存发展,总是要出门谋生,不是打猎捕鱼,就是砍柴种地。出行在外,风云不 People living in the world, inseparable from the basic necessities of life. Because of the very low productivity of the ancients at that time, living conditions were naturally primitive and simple. Primitive cave, is to shelter from the beast. After gradually getting a humble home, the general storm is no longer a threat. However, human beings have to survive and develop. They always want to go out for a living, not to hunt for fishing or to cut firewood. Travel outside, the situation is not