Practice with topic sentences

　　The topic sentence states the topic and a controlling idea concerning that topic .Look at the following example.
People give many reasons for "owning a car." The controlling idea is "reasons." All the supporting ideas in the paragraph should be "reasons for owning a car."
　　The following phrases or ones similar to these can be used in your topic sentence to express the controlling idea:
the reasons for ……的理由
the causes of(the effects of) ……的原因、起因
the steps for(the procedure for) 步骤、程序
the advantages of(the disadvantages of) ……的优势（劣势）
the ways to(the methods of) 做……的方法、途径
the different sections(parts, kinds, types) of 不同的部分（种类、类型）
the characteristic(traits, qualities) of 特征、特点
the problems of 问题
the precautions of 预防措施
the changes to 变化

Checking topic sentences

　　Your topic sentence should tell the person who is reading your paragraph what the paragraph is about. Read the following paragraph and decide whether the topic sentence is strong or weak. (The topic sentence is underlined.)

　　Baseball is a popular sport in the United States. There are two teams of nine players each. Players on one team take turns batting, and other team tries to put the batters out. The batter hits the ball and then tries to run around the bases and get "home" safely. The other team tries to put the batter out by catching the ball before it hits the ground, throwing the ball to the base before the batter gets there or by tagging the batter with the ball. The batter can stop at any one of the three bases if it is impossible to make it "home."
　　The topic sentence in the paragraph is weak because it tells us that "baseball is a popular sport ", but the rest of the paragraph tells us how baseball is played. A stronger topic sentence would tell us, the readers that the paragraph is going to describe how baseball is played. Here is a stronger topic sentence.
Baseball, a popular game in the United States, is played in the following way. Now the reader knows that the paragraph will describe how baseball is played instead of where it is played or who plays it, or why it is popular.

1. Even though the procedures followed to enroll in an American university vary according to each university, some steps are the same. First, you should contact the registration office of the university you want to attend to get the necessary forms and information concerning that particular university's entrance requirements. Then you must follow the steps outlined in their response. You will probably have to send copies of your high school diploma, get letters of recommendation, and write an essay on why you want to study there. You may have to achieve a certain score on the TOEFL test and have your scores forwarded to the university. Finally, you will have to contact the American embassy to start the procedures to obtain a student visa.

2. I like to go to the beach whenever I have the opportunity. I start the day by enjoying a refreshing swim. Then I walk along the beach and collect shells. Later you'll find me relaxing in the warm sunshine and making sand castles. Then I sleep for a while before I open the basket of food and drinks that I always pack to take.

3. Many students can not afford a car. The city bus service usually passes the university, so those students can get to class on the bus. Many universities have a special shuttle bus that is provided for student transportation. Some students like to ride to class on bicycles. This is good exercise. Also, it is easier to find a space to leave a bicycle than to find a parking space for a car on a crowded university campus. Those students who live close to campus or on campus can enjoy a leisurely walk to their classes.
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