176.As a popular saying goes, everything has two sides. Now the public are benefiting more and more from scientific and technological inventions.On the other hand, the progress of science and technology is bringing us a lot of trouble.People in many countries are suffering from public hazards.
177.Let''s take cars for example.They not only pollute the air in cities, but make them crowded.Furthermore, they are responsible for a lot of traffic accidents.The noise made by cars disturbs the residents living on both sides of streets all day and night.
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.
179.There is no doubt that the increase in demand caused the rise in prices.
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.
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.
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.
183 Tourism, however, gives rise to a number of problems.For instance, it becomes a burden to inefficient transportation system.
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.
185.As for me, with the development of our national economy, all these problems will certainly be solved step by step.
186.A much better and brighter future awaits us.
187.When an opportunity comes, it brings a promise but never realizes it on its own.
188.If you want to achieve something or intend to fulfill one of your ambitions, you must work hard, make efforts and get prepared.Otherwise, you will take no advantage of opportunities when they come to visit you.
假如你要取得成就或要实现你的雄心壮志，你必须努力工作、艰苦奋斗、准备好条件。否则，机遇来临你却无法利用。 189.The difference between a man who succeeds and one who does not lies only in the way each treats opportunities.The successful person always makes adequate preparations to meet opportunities as they duly arrive.The unsuccessful person, on the other hand, works little and just waits to see pass by.