Exercise is beneficial to your heart. A 22-year study was conducted by doctors in California. They found that people who work at physical jobs experience fewer heart attacks than other people. These active people work all the time at moderate speeds, their daily routine gives them an adequate amount of exercise and helps them stay in shape.
“Exercise is beneficial”這是毫無(wú)疑義的。但主題句中如不加上“to your heart”來(lái)加以 control 和 limit,那就流于空泛。
因此,緊緊把握主題句中controlling idea的導(dǎo)向和制約作用,是短文寫(xiě)作成功關(guān)鍵之一。
2.推展句
2.1 主要推展句
主要推展句（major supporting statement）的主要特點(diǎn)是：圍繞段落主題句展開(kāi)的每一個(gè)推展句本身都不要求作進(jìn)一步的說(shuō)明或證明,句與句之間的關(guān)系是相互獨(dú)立又是互相連接的。
例1：（主題句） There are several factors affecting climate. （推展句1）One factor is the mount of sunlight received. （推展句2）Altitude, or the height above sea level, also determines climate. （推展句3）The oceans have an effect on the climate of adjacent land. （推展句4）In addition, climate is influenced by the general circulation of the atmosphere.
主題句指出影響氣候的幾個(gè)因素。然后用四個(gè)擴(kuò)展句說(shuō)明四種因素。第一種是太陽(yáng)光的接收量,第二種是海拔高度,第三句和第四句分別是海洋和大氣環(huán)流因素。
2.2 次要推展句
次要推展句（minor supporting statement）是指對(duì)主要推展句作進(jìn)一步的事實(shí)分析和舉例說(shuō)明。它從屬于某一個(gè)或某幾個(gè)推展句。
例2：（主題句）I don't teach because teaching is easy for me. （主要推展句1）Teaching is the most difficult of the various ways I have attempted to earn my living： mechanic, carpenter, writer. （主要推展句2）For me, teaching is a red-eye, sweaty-palm, sinking-stomach profession. （次要推展句1）Red-eye, because I never feel ready to teach no matter how late I stay up preparing. （次要推展句2）Sweaty-palm, because I'm always nervous before I enter the classroom, sure that I will be found out for the fool that I am. （次要推展句3）Sinking-stomach, because I leave the classroom an hour later convinced that I was even more boring than usual.
從屬于主要推展句2的三個(gè)次要推展句起著解釋說(shuō)明作用,分別解釋red-eye, sweaty-palm, sinking-stomach的含義,這就更加形象生動(dòng)地證明了 “teaching is not easy” 這個(gè)主題。
2.3 主要推展句與次要推展句的關(guān)系
主要推展句與次要推展句的關(guān)系（relation）基本可以遵循下面的“三部分”（three-part）規(guī)則。
1〕每個(gè)主要推展句都應(yīng)該是對(duì)主題句中表示主要思想的關(guān)鍵詞的直接、明確的說(shuō)明。
2〕每個(gè)次要推展句都應(yīng)該說(shuō)明它的主要推展句。
3〕含有討論說(shuō)明或分析的問(wèn)題通常既要有主要推展素材,又要有次要推展素材。
“Exercise is beneficial”這是毫無(wú)疑義的。但主題句中如不加上“to your heart”來(lái)加以 control 和 limit,那就流于空泛。
因此,緊緊把握主題句中controlling idea的導(dǎo)向和制約作用,是短文寫(xiě)作成功關(guān)鍵之一。
2.推展句
2.1 主要推展句
主要推展句（major supporting statement）的主要特點(diǎn)是：圍繞段落主題句展開(kāi)的每一個(gè)推展句本身都不要求作進(jìn)一步的說(shuō)明或證明,句與句之間的關(guān)系是相互獨(dú)立又是互相連接的。
例1：（主題句） There are several factors affecting climate. （推展句1）One factor is the mount of sunlight received. （推展句2）Altitude, or the height above sea level, also determines climate. （推展句3）The oceans have an effect on the climate of adjacent land. （推展句4）In addition, climate is influenced by the general circulation of the atmosphere.
主題句指出影響氣候的幾個(gè)因素。然后用四個(gè)擴(kuò)展句說(shuō)明四種因素。第一種是太陽(yáng)光的接收量,第二種是海拔高度,第三句和第四句分別是海洋和大氣環(huán)流因素。
2.2 次要推展句
次要推展句（minor supporting statement）是指對(duì)主要推展句作進(jìn)一步的事實(shí)分析和舉例說(shuō)明。它從屬于某一個(gè)或某幾個(gè)推展句。
例2：（主題句）I don't teach because teaching is easy for me. （主要推展句1）Teaching is the most difficult of the various ways I have attempted to earn my living： mechanic, carpenter, writer. （主要推展句2）For me, teaching is a red-eye, sweaty-palm, sinking-stomach profession. （次要推展句1）Red-eye, because I never feel ready to teach no matter how late I stay up preparing. （次要推展句2）Sweaty-palm, because I'm always nervous before I enter the classroom, sure that I will be found out for the fool that I am. （次要推展句3）Sinking-stomach, because I leave the classroom an hour later convinced that I was even more boring than usual.
從屬于主要推展句2的三個(gè)次要推展句起著解釋說(shuō)明作用,分別解釋red-eye, sweaty-palm, sinking-stomach的含義,這就更加形象生動(dòng)地證明了 “teaching is not easy” 這個(gè)主題。
2.3 主要推展句與次要推展句的關(guān)系
主要推展句與次要推展句的關(guān)系（relation）基本可以遵循下面的“三部分”（three-part）規(guī)則。
1〕每個(gè)主要推展句都應(yīng)該是對(duì)主題句中表示主要思想的關(guān)鍵詞的直接、明確的說(shuō)明。
2〕每個(gè)次要推展句都應(yīng)該說(shuō)明它的主要推展句。
3〕含有討論說(shuō)明或分析的問(wèn)題通常既要有主要推展素材,又要有次要推展素材。