两个或两个以上简单句 (Simple Sentence) 可以合成一个较长的简单句、并列句 (Compound Sentence) 或复杂句 (Complex Sentence) .通过句子的合成，我们得以更清楚地看出句子间的语义关系，而且还可以使句子多样化，增加文章的丰姿。
现在就从三方面来看看句子合成法的问题。
1. 由两三个简单句合成一个长的简单句。例如：
(1) John ran away. He escaped the danger. → Running away， John escaped the danger. )
(2) The hunter took up his gun. He shot the boar. → The hunter took up his gun to shoot the boar.
(3) The king died. The queen heard about it. She fainted. → On hearing about the king's death， the queen fainted.
(4) Kelvin is my good friend. He is a strong supporter of social justice. → Kelvin， a strong supporter of social justice， is my good friend.
(5) The rascal kicked the cat. He kicked it on the back. He kicked it intentionally. → The rascal kicked the cat on the back intentionally.
2. 由两三个简单句合成一个并列句。例如：
(6) John was sad. He kept quiet. → John was sad but he kept quiet.
(7) Take the book. Leave it there. → Take the book or leave it there.
(8) Sean did not come to class today. He had a bad headache. → Sean did not come to class today， for he had a bad headache.
(9) Bruce was lying on the bed. He looked at the ceiling. He saw a lizard. → Lying on the bed， Bruce looked at the ceiling and saw a lizard.
3. 由两三个简单句合成一个复杂句。例如：
(10) Kelvin is getting rich. We know about it. → We know that Kelvin is getting rich.
(11) I like this book. It contains many amusing stories. → I like this book which contains many amusing stories.
(12) Helen is sure to get her pay. It is due to her. Why does she complain? → Why does Helen complain since she is sure to get the pay due to her ?
(13) The woman was exhausted. She had not slept well the previous night. → The woman was exhausted because she had not slept well the previous night.
上面例子显示，简单句由“主语 + 谓语” (Subject + Predicate) 构成，有时还附有修饰性的短语。并列句由至少两个地位平等的并列分句透过并列连词 (Coordinating Conjunction) 如“ and， or， but， so， for ”等连成。复杂句包括一个主句 (Main Clause) 及至少一个从句 (Subordinate Clause) ， 通过从属连词 (Subordinating Conjunction) 如 “That， since， because， when， if ”等合成。从属分句因功能不同而分成“名词从句” (Noun Clause)， “副词从句” (Adverb Clause) 和“形容词从句” (Adjective Clause) .上述诸句式中，复杂句最为多采多姿，不妨多用。为了避免句子太长，难以控制，一个复杂句最好不要超过三个从句。
（责任编辑:doublejp）
