Exercises1. Revise topic sentences. Topic sentences as below are not effective one. Try to find out what is wrong and revise them.Model:Original: Columbus was an explorer in the 1400s.Revision: Travel has changed since the days of Columbus.(1) Original: Internet is the topic of the paragraph.Revision: (2) Original: I had a very bright student long ago.Revision: (3) Original: People waste timeRevision: (4) Original: Every extra hour of watching television meant an 8% increase in the chances of developing signs of depression.Revision:(5) Original: Failure is the mother of success and fearing mistakes prevents us from making change and slow down personal progress.Revision:2. Identify the topic sentence in each of the following paragraphs. Supply a topic sentence if there is no explicit one in it. (1) Opera in the 19th century developed in two main ways. Fist, there was the type that preferred to give the greatest importance to the voice, keeping the orchestra more as an accompaniment. And second, there was the type that reduced the importance of the singers and allowed the orchestra to dominate the proceedings. The first type could be described as OPEAR OF VOCAL MELODY. You can fid examples in the work of Rossini, Belline, Donizetti, and of course, Verdi, The second type is really SYMPHONICOPERA. Wagner is its most important exponent. (2) Increasingly over the past ten years, people have become aware of the need to change their eating habits, because what we choose to eat can influence our healthfor better or worse Consequently, there has been a growing interest in natural foods. (3) Of all human emotions, none is more natural than the love for the town, the valley or the neighborhood where we grew up. Our homeland speaks to our most intimate memories, moves our deepest emotions. Everything that is a part of it belongs to us in some measure. In a way we belong to it, too, as a leaf belongs to a tree.(4) Standing in the Sicilian sun with your feet washed by the waves of the Tyrrhenian Sea, its easy to forget that theres more to the tri-corner island than beauty. The beaches are magnificentturquoise waters stretching out to the horizon, soft sand, gentle waves and some of the clearest water in the world. In the distance, on the rockier portions of the coast, volcanic rock juts out of the sea, its dark color and jagged edge adding drama to the vista.3. Choose a right topic sentence for each of the following paragraphs and give a reason for your choice.(1) Para: A study found that people who rated themselves highly stressed had lower levels of stress hormones after eating chocolate every day for two weeks. The studys subjects ate 1.4 ounces(40g) of dark chocolate daily.Topic sentences:a. You can eat chocolate every day.b. Eating chocolate every day can reduce stress.c. Certain elements in chocolate can have helpful health benefits.(2) Para: Social pressures are breaking apart more and more American homes. Over half of U.S. marriages now end in divorce. More than one in four American children are growing up in single-parent homes.Topic sentences:a. Families in America face many problems. b. American children suffer a lot from their broken family.c. peole realize that problems in family life have brought about serious consequences.(3) Para: More than half of the 3 million annual visitors come to Yellowstone National Park in July and August. In September and early October, the weather is good, the visitors few, and the wildlife abundant. In May and June, you can see newborn animals, but the weather may be cold, wet, and even snowy. Between about November through April most park roads are closed to vehicles.Topic sentences:a. The best time to visit Yellowstone National Park is from September to October.b. Yellowstone National Park is the oldest and largest national park in the United States.c. People can enjoy seeing the beautiful scenery and live animals in Yellowstone National Park.4. Use the topic sentences given below to form paragraphs of four to five sentences. You may put your topic sentence where you think it will be most appropriate.Model: Topic sentence: Colleges take different measures to tackle H1N1 flu.In order to control the situation, colleges began to take different measures to tackle H1N1 flu. After eight freshmen at the school were found to have caught the H1N1 virus, the Northeast University blocked all entry and exit from student dorms as a precautionary step to keep it from spreading. Compared to Northeasts tough policies, Heilongjiang University took different approach by just letting all the students go home. Universities like Jinan and South China Agriculture canceled their military training to prevent an outbreak on campus.(1) Every hour of every day is a bonus.(2) The history shows that it is always cheaper to prevent emissions than to reverse any damage they cause.(3) The more