178. It is generally believed that the chief reason for the increase in population in developed countries is not so much the rise in birth rates as the decline in death rates as a result of the improvement in medical care.
普遍认为，在发达国家人口增长的主要原因与其说是出生率的上升，还不如说是由于医疗保健的改善使死亡率下降了。
179. There is no doubt that the increase in demand caused the rise in prices.
毫无疑问，需求的增长导致了价格的上涨。
180. Additional social stresses may also occur because of the population explosion or problems arising from mass migration movements-themselves made relatively easy nowadays by modern means of transport.
由于人口的猛增或大量人口流动（现代交通工具使这种流动相对容易）引发的种种问题也会对社会造成新的压力。
181. With the opening and reform policy being carried out, thousands upon thousands of foreign visitors are crowding into our country. They are eager to see this old mysterious land with a splendid culture of more than 5,000years.
随着改革开放政策的贯彻执行，数以万计的外国游人涌入中国。他们渴望参观这个有着5000多年灿烂文化的神秘古国。
182. Tourism brings China a lot of benefits. First, it enables the Chinese people to know more about the outside world and promotes friendship and understanding. Second, it is financially beneficial to China, which needs more foreign currencies for its modernization program.
旅游业给中国带来许多好处。首先，它使中国人了解外界，并有助于促进友谊和理解。其次，在经济上也有利于我国，因为中国现代化建设需要大量的外汇。
183 Tourism, however, gives rise to a number of problems. For instance, it becomes a burden to inefficient transportation system.
旅游业也引起许多问题。例如，它增加了我国本来效率不高的运输系统的负担。
184. Besides, the living standard of the average Chinese is still not high enough to be able to afford the many different sorts of expensed during long distance travels.
此外，中国人民的生活水平还没有高到足以使普通中国人有钱支付长途旅行的各种开支。