我们在写作中肯定会用一些句子，但是托福写作句子需要哪些特性呢?北京新航道小编举例说明了一些信息，供大家参考学习。

　　1.统一性

　　一个段落内的各个句子必须从属于一个中心，任何游离于中心思想之外的句子都是不可取的。请看下例：

　　Joe and I decided to take the long trip we‘d always wanted across the country. We were like young kids buying our camper and stocking it with all the necessities of life. Bella bakes the best rhubarb pie. We started out in early spring from Minneapolis and headed west across the northern part of the country. We both enjoyed those people we met at the trailer park. Joe received a watch at his retirement dinner. To our surprise, we found that we liked the warm southern regions very much, and so we decided to stay here in New Mexico。

　　本段的主题句是段首句，controlling idea(中心思想)是take the long trip across the country。文中出现两个irrelevant sentences，一个是Bella bakes the best rhubarb pie，这一段是讲的是Joe and I ，中间出现一个Bella是不合适的。

　　2.完整性

　　正象我们前面说得那样，一个段落的主题思想靠推展句来实现，如果只有主题句而没有推展句来进一步交待和充实，就不能构成一个完整的段落。同样，虽然有推展句，但主题思想没有得到相对圆满的交待，给读者一种意犹未尽的感觉。这样的段落也不能完成其交际功能。例如：

　　Physical work can be a useful form of therapy for a mind in turmoil. Work concentrates your thoughts on a concrete task. Besides, it is more useful to workyou produce something rather than more anxiety or depression。

　　本段的主题句是段首句。本段的两个推展句均不能回答主题句中提出的问题。什么是 "a mind in turmoil"(心境不平静)Physical work又如何能改变这种情况?为什么它能起therapy的作用?读者得不到明确的答案。

　　3.连贯性(coherence)

　　连贯性包括意连和形连两个方面，前者指的是内在的逻辑性，后者指的是使用转换词语。当然这两者常常是不可分割的。只有形连而没有意连，句子之间就没有内在的有机的联系;反之，只有意连而没有形连，有时行文就不够流畅。

　　1) 意连

　　段落中句子的排列应遵循的次序，不能想到什么就写什么。如果在下笔之前没有构思，边写边想，写写停停，那就写不出一气呵成的好文章来。下面介绍几种常见的排列方式。

　　A.按时间先后排列(chronological arrangement)

　　We had a number of close calls that day. When we rose, it was obviously late and we had to hurry so as not to miss breakfast; we knew the dining room staff was strict about closing at nine o‘clock. Then, when we had been driving in the desert for nearly two hours - it must have been close to noonthe heat nearly hid us in; the radiator boiled over and we had to use most of our drinking water to cool it down. By the time we reached the mountain, it was four o‘clock and we were exhausted. Here, judgement ran out of us and we started the tough climb to the summit, not realizing that darkness came suddenly in the desert. Sure enough, by six we were struggling and Andrew very nearly went down a steep cliff, dragging Mohammed and me along with him. By nine, when the wind howled across the flat ledge of the summit, we knew as we shivered together for warmth that it had not been our lucky day。

　　本段从 "rose"(起床)写起，然后是吃早餐("not to miss breakfast", "closing at nine o‘clock")，然后是 "close to noon"，一直写到这一天结束("By nine")。

　　上面就是托福写作句子需要的一些特性，同学们在备考要注意积累和运用这些特性。北京新航道小编预祝各位考试取得优异的成绩。

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