topic sentence英语主题句.doc

主题句是一个完整的句子，用以概括、叙述或说明该段落的主旨大意。每一个段落只能有一个主题，全段的其他文字都应围绕它展开。主题句通常由两部分组成，即主题 (topic) +中心思想 （controlling idea）。中心思想的作用是导向 (control) 和制约 (limit) 主题。所谓导向就是规定段落的发展脉络，所谓制约就是限制主题的覆盖范围，两者不可分割。没有导向，内容就会离题或偏题；没有制约，内容就可能超出一个段落所能容纳的范围。下面的8个句子都是很漂亮的主题句，其中红色加粗的文字为主题，绿色斜体的文字为中心思想： 1. People can avoid burglaries（入室行窃） by taking certain precautions.? ( 接下来作者将围绕着“防范措施”展开段落) 2. There are several advantages to growing up in a small town.? ( 接下来作者将围绕着“优点”展开段落) 3. Most US universities require a 550 point TOEFL score for a number of reasons.? ( 接下来作者将围绕着“原因”展开段落) 4. Fixing a flat tire on a bicycle is easy if you follow these steps.? ( 接下来作者将围绕着“步骤”展开段落) 5. There are several enjoyable ways to travel between the US and Queretaro.? ( 接下来作者将围绕着“方法”展开段落) 6. Effective leadership requires specific qualities that anyone can develop.? ( 接下来作者将围绕着“品质”展开段落) 7. Industrial waste poured into Pearl River has led to dramatic changes in its ability to support marine life.? ( 接下来作者将围绕着“变化”展开段落) 8. In order to fully explore the wreck（残骸） of the Titanic, scientists must address several problems.? ( 接下来作者将围绕着“问题”展开段落) 通过对上面8个主题句的分析可见：段落的主题句对主题的限定主要是通过句中的关键词来实现的。也就是说，中心思想中应包含着一个相对具体的关键词（用下划线标出）。对 “具体” 的要求包括两个方面：一是要具体到能控制和限制段落的发展；二是要具体到能说明段落的展开方法。 Exercise B There is something wrong with the following topic sentences, please rewrite them to make them effective. 请找出下面4个主题句存在的问题并进行修改。 1. My hometown is famous because it is located by Wheaton River, which is very wide, and because it is built near an unusually steep hill called Wheaton Hill. 2. Stephen Hawkings physical disability（残疾）has not prevented him from becoming a world-renowned physicist, and his book is the subject of a movie. 3. Many Americans