求翻译：4、不受时间和空间的限制，任人随意欣赏，具有长期的时效性。 5、成本较低。按千人成本计算，户外广告成本较低。 6、生命周期长。户外广告一般时间较长，有利于需要重复强化的信息。是什么意思？

4, free from the constraints of time and space, as the fancy free to enjoy the long-term aging. 5, relatively low cost. According to the calculation of cost per thousand, lower outdoor advertising costs. 6, the life cycle. Outdoor advertising is generally a long time, and is conducive to information

4th, not the time and the spatial limit, lets the human to appreciate at will, has the long-term effectiveness. 5th, the cost is low.According to thousand human of cost findings, the outdoors advertisement cost is low. 6th, the life cycle is long.The outdoors advertisement general time

4, is not limited by time and space, anyone feel free to appreciate, with a long time. 5, and lower costs. On a CPM basis, outdoor advertising is less expensive. 6, and long life cycle. Outdoor advertising in General for a long time, in favour of the need to repeat intensive information.