Unity & Coherence
Unity 统一性
段落中每一句均须与此段的主题相关，并提供资料来支持主题，句子间必须先后有序，合乎逻辑，否则便会欠缺统一性。当你写下一段落时，必须检查每句的内容是否依据主旨，如果不是的话，便要修改或移到另一段。
例如：
Learning a foreign language has changed. Not long ago, students would sit with pen in hand, writing the basic forms of a language, learning structures they would never be able to speak. In that same classroom today, pens and notebooks have been put away. The spoken sounds of foreign tongue fill the room. Today the last skill learned --- writing a foreign language --- comes as a natural and possible part of the total language-learning process. Yet, just a few years ago, the last skill learned was the first skill mastered today --- speaking a foreign tongue.To visit some foreign countries, travelers have to apply for visas.
Topic sentence: Learning a foreign language has changed.
*不统一句子：To visit some foreign countries, travelers have to apply for visas.
由以上段落可见每句均围绕主旨而发展，主题句：学习外语已经改变了，但当中有一句：To visit some foreign countries, travelers have to apply for visas.则是说申请护照的，明显地不合此段主题 learning a foreign language，所以必须移走此句，才使本段意思归一。
Coherence 连贯性
段落除了须要统一性及文字流畅外，还要句与句，字与字之间有连贯性，要达到此点，便须作出适当排序，如果一段落内句子不统一，则即使有连贯性也没用，反之，若没有连系的句子乱成一团，就算全部与主旨有关，也是令读者看不懂，所以，要做好构段，unity 及coherence二者缺一不可。要令一段落有连贯性，可使用transitional words，现以第二课的练习说明之（注意黑体部分）：
Times Squares is unquestionably the center of entertainment in New York City.There are nearly a hundred Broadway theaters and Off-Broadway stages. People can choose many kinds of musicals from international well-known classical tolively and unusual productions. For example, I have seen several Broadway shows like “Cats” and “Miss Saigon.” I enjoyed the emotional songs and experienced their joys and sadness. Besides Broadway theaters, there are a lot of movie theaters in which most recent Hollywood first-run films are shown. People can see different popular films and spend a whole day in these theaters. Moreover, during lunchtime, there are some street performances such as Jazz and Hard Rock. People crowd the street and listen to ethnic and experimental music with special sound effects. As a result, no one feels bored in Times Squares as it brings her or him a rich variety of entertainment like Broadway musicals, movies and street shows.
从以上段落中，可以找到一些transitional words，即 For example, Besides, Moreover, As a result, 用以增加句子之间的连贯性，令段落安排更有次序，而透过这些转折词及字，令读者亦易于明白和找到支持主旨的理据 Supporting Details。
Exercise:
Choose one of the following topic sentences, and write a plan for a paragraph.First, copy the topic sentence, and then list three to four points to support it. Finally, make your conclusion.
