1 . Sentence fragments
Make sure each word group you have punctuated as a sentence contains a grammatically complete and independent thought that can stand alone as an acceptable sentence.
我经常看到句子成分不全，或者两个句子不加任何连词的用在一起的情况，出现这种情况的原因有两个：
1是句子太长，把作者自己搞晕了
2是有些人还不清楚两个完整的句子不能排在一起而不加任何连词。
还有一种情况是一个完整的单句带有有连词，却没有主句。或者将一个主从句断裂开了。第二个例句就是此类。
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Sentence Fragment
Tests of the Shroud of Turin have produced some curious findings. For example, the pollen of forty-eight plants native to Europe and the Middle East.
[2nd sentence = fragment]
改正：
Tests of the Shroud of Turin have produced some curious findings. For example, the cloth contains the pollen of forty-eight plants native to Europe and the Middle East.
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原句：
Scientists report no human deaths due to excessive caffeine consumption. Although caffeine does cause convulsions and death in certain animals.
改正：
[2nd sentence = fragment]
Scientists report no human deaths due to excessive caffeine consumption, although caffeine does cause convulsions and death in certain animals.
2. Sentence sprawl
Too many equally weighted phrases and clauses produce tiresome sentences.
过尤不及，虽然我们强调句子要有一定的复杂性，但是实际上老米教授、专家从来不主张过长的句子，读者也不爱看。不过，要达到精确而又不啰嗦的表达，的确是有难度的。
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Sentence sprawl
The hearing was planned for Monday, December 2, but not all of the witnesses could be available, so it was rescheduled for the following Friday, and then all the witnesses could attend.
[There are no grammatical errors here, but the sprawling sentence does not communicate clearly and concisely.]
改正：
The hearing, which had been planned for Monday, December 2, was rescheduled for the following Friday so that all witnesses would be able to attend.
3. Misplaced and dangling modifiers
Place modifiers near the words they describe; be sure the modified words actually appear in the sentence.
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Misplaced or Dangling Modifier
When writing a proposal, an original task is set for research.（错位）
改正：
When writing a proposal, a scholar sets an original task for research.
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原句
Many tourists visit Arlington National Cemetery, where veterans and military personnel are buried every day from 9:00 a.m. until 5:00 p.m.
本句最后是一个dangling modifer悬虚的修饰成分，让人产生误解，此成分应该靠近发出动作的人或物
改正：
Every day from 9:00 a.m. until 5:00 p.m., many tourists visit Arlington National Cemetery, where veterans and military personnel are buried.
4. Faulty parallelism
Be sure you use grammatically equal sentence elements to express two or more matching ideas or items in a series.
平行结构是很容易出错的，在托福语法中也是出题点，这种错误很容易被忽视。英语我们的是非母语，在语感上来识别错误的可能就降低了。写作和检查的时候注意主胃、动宾的搭配、一致，主动被动的转换。
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Faulty parallelism
The candidate‘s goals include winning the election, a national health program, and the educational system.
改正：
The candidate‘s goals include winning the election, enacting a national health program, and improving the educational system.
原句：
Some critics are not so much opposed to capital punishment as postponing it for so long.
改正：
Some critics are not so much opposed to capital punishment as they are to postponing it for so long.
5. Unclear pronoun reference
All pronouns must clearly refer to definite referents [nouns].
Use it, they, this, that, these, those, and which carefully to prevent confusion.
错误的使用代词或模糊的是用代词，是我经常在论坛作文里面发现的。不是说不可以用，但是一定要很清楚地有所指。作文的开头部分，我的建议是尽量不要用很多代词，因为开头部分是整个文章的一个概览，thesis必须clear, 不要怕麻烦，即便是多陈述一遍（不要用原句！换换说法），也是对thesis的强调，并不累赘。正文、结尾只要使用代词得当就可以了。
不要小看代词，它对你思想的表达有的时候很关键，如果指代不清，其他写得再好读者也会confused
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Unclear pronoun reference
Einstein was a brilliant mathematician. This is how he was able to explain the universe.
改正：
Einstein, who was a brilliant mathematician, used his ability with numbers to explain the universe.
原句：
Because Senator Martin is less interested in the environment than in economic development, he sometimes neglects it.
- 考试辅导
