One that contains at least a subject and a predicate(or finite)verb .
If the verb is transitive,there must be an object ； eg: She wrote a letter.
If the verb is link-verb,there must be a predicate or complement. eg: My mother is a teacher.
A complete sentence begins with a capital letter and ends with a period.
Sentence Fragment
Whitout a subject or a predicate verb .
Sometimes experienced writers use incomplete sentences for special effect.
Effective Sentences
Unity (统一性）
The first quality of an effective sentence.
A unified sentence expresses a single complete thought.
Coherence(连贯性）
It means clear and reasonable connection between parts.
It must avoid
Wrong parallel structure(错误的平行结构）
A pronoun with ambiguous reference(代词指代不明）
The dangling modifier leads to the inconsistency between subject and predicate.(悬垂修饰语导致主谓不一致）
Misplaced modifier(错位修饰语）：because of a confusing change in person number , in mood , in tense , in voice ,in discourse , and in sentence construction respectively.
Conciseness(简洁性）
A sentence should contain no unnecessary words.
It must avoid
Chinglish(中式英语）：Chinese language tends to tolerate more repeated modifies than English.
Unnecessary repetition: including
unnecessary nouns, eg: the key to the solution lies in...中the key to 就是多余的
unnecessary verbs, eg: make an improvement就可以直接用improve
unnecessary modifiers： redundant modifiers（冗杂的修饰语) eg: adj. 和 n.词义重复; 时间状语in the future 和 soon; intensifiers(加强语气的）eg: I firmly believe可以改为I'm convinced that
Emphasis(强调性）
Emphatic sentences(强调的句子）
Short sentences
Sentence fragments
Inverted sentences(倒装句）
Parallel constructions and balanced sentences
Periodic sentence
Imperative and exclamatory sentences（祈使句和感叹句)
Rhetorical questions（修饰性的反问句）
Negative-positive statements(正话反说）
Sentences with repeated words or phrases
Emphasis whthin the sentence(句子内部的强调）
Placing（放置位置）：the beginning and the end, especially the end)
Repetition（重复）
The verb and the active voice（动词和主动语态）
Subordination（从属关系）
Emphatic words and phrases（强调的词和短语）
Allteration( 头韵）
Variety(多样性）
It can avoid monotonous.（避免单调）
Changes in sentence patterns（句式的变化）
The structure and length of sentences（句子的结构和长度）
等等
Types of Sentences
Use（用途）
Declarative Sentence(陈述句)
Interrogative Sentence(疑问句）
Yes or No Question
"Question Word"Question
Choice Question
Imperative Sentence（祈使句）
Exclamatory Sentence（感叹句）
Structure（结构）
Simple Sentence (简单句）
A group of subjects and a group of predicates(有一组主语和一组谓语) 1. A Sentence has only one subject and one predicate verb, but it may contain more than one object, attribute or adverbial. 2. A sentence with two or more subjects or predicate-verbs. eg: He and his brother went to town and bought a pile of books.
Compound Sentence(复合句）
Two or more main clauses(多个主句) 1. A compond sentence consists of two or more indepebdent clauses;2.linked by a coordinating conjunction; 3.by a colon( : ), dash(--), semicolon( ; ) without a conjunction.
Complex Sentence（复杂句）
One main clause and one or more dependent clauses(一个主句并且至少有一个从句）
Compound-Complex Sentence(复合复杂句）
At least two main clauses and at least one dependent clause(至少两个主句和一个从句）
Feature: It puts first thing first; in other words , it puts the main idea before all supplementary information.(重要的事情放在开头) Advantages: easier , simpler , more natural and direct. Disadvantages:Readers are easy to lose contral and close thier minds.
Periodic Sentence(圆周句）or Suspended Sentence(延后句）
Feature: The main idea is expressed at or near the end of sentence for emphasize climax.(前面铺垫，高潮放在后面) Advantages:complex , emphatic , formal , literacy and persuasive. Disadvantages:Reasers will get bored and stop reading.
Balanced Sentence(平衡句)
Features: A sentence contains two parallel clauses similar in structure but contrasted in meaning.(两个平行句子结构相似，意思不同） Advantages:impressive and rhythtic
Length(长度）
Short Sentence（短句）
1.Short sentences are usually emphatic;
2.Short sentences are suitable for the presentation of important facts and ideas.
Long Sentence (长句）
1.Long sentences are capable of expressing complex ideas with precision,because it may contain many modifiers.
2.Long sentences for the explanation of views and theories,or the description of things with many details.
