In syntax, a sentence with an independent clause and at least one dependent clause (subordinating clause) is referred to as a complex sentence. The dependent clause is introduced by either a subordinate conjunction such as although, while or because or a relative pronoun such as who or which.

Examples

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• When I saw what you have done, I was happy.
  • Independent clause: I was happy.
  • Dependent clause: When I saw what you have done

• That you love me makes me happy.
  • A complex sentence with a sub-clause functioning as a subject.
  • Independent clause: (subject) makes me happy.
  • Dependent clause: That you love me (acting as the subject)

• It makes me happy that you love me.
  • A clefted complex sentence with a sub-clause indicating what the dummy pronoun "It" refers to.
  • Independent clause: It makes me happy.
  • Dependent clause: that you love me

• The book is where you have put it.
  • A complex sentence with a sub-clause functioning as subject complement. "Be" is a copula verb; it links the sub-clause to the subject.
  • Independent clause: The book is (complement).
  • Dependent clause: where you have put it (acting as the complement)

Contrast

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• I ate the meal which you cooked.

I ate the meal is an independent clause and which you cooked is relative clause. A sentence with a relative clause, a clause that has no function but describes its noun phrase, does not fulfill the dependent clause requirement of a complex sentence. A sentence is complex only when it contains a subordinate clause which fulfills a syntactic function within the sentence. In the first example above, the sub-clause When I saw what you had done is adverbial; it has a temporal meaning. The sub-clause what you had done is embedded in the first sub-clause and functions as direct object for the transitive verb "to see".

• I was scared, but I didn't run away.

Both clauses are independent. Therefore, this is a compound sentence but not a complex sentence.

• The dog ^* you gave me barked at me and bit my hand.

This is a complex-compound sentence with two independent clauses (The dog you gave me barked at me and The dog ^* you gave me).

See also

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• Simple sentence
• Compound sentence
• Complex-compound sentence

External links

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• The Structure of a Sentence

Syntax | Grammar