• Sentences are the highest element in the “grammatical hierarchy.” Their constituents are clauses, the second highest element.
• All simple and complex sentences consist of a single main clause. Compound sentences consist of two or more main clauses. The main clause of a simple or complex sentence is always independent (i.e. one that is capable of standing by itself as a sentence.)
• Functionally, sentences can be classified as:
declarative: “You may sit down there” or interrogative: “Would you like to sit down?” or imperative: “Sit down!”
• Structurally, sentences can be classified as:
a simple sentence consists of only one independent clause none of whose immediate constituents is itself a clause. For example:
Harry’s daughter is studying music in Italy.
- The independent clause —Harry’s daughter is studying music in Italy— is the unitary constituent of the simple sentence—Harry’s daughter is studying music in Italy.
(An “independent clause” is a clause which could stand alone as a well-formed sentence.)
- Even though none of the immediate constiutents of a simple sentence can be a clause, a simple sentence can contain a clause as a non-immediate constituent: —Harry’s daughter, whom I met last year, is studying music in Italy. is a simple sentence even though it contains the subordinate clause, whom I met last year; this is because the subordinate clause is not an immediate constituent of the sentence but is embedded in the subject element.
a compound sentence consists of two or more main clauses joined by a coordinating conjunction.
Harry’s daughter is studying music in Italy and his son is studying medicine in Japan.
- both the main clauses in the above example are independent clauses. Often, however, one of the coordinated clauses in a compound sentence is not independent because of ellipsis. For example, Harry’s daughter is studying Italian in Italy and living with an Italian family.
a complex sentence consists of one main clause and at least one subordinate clause acting as an immediate constituent.
Harry met his first wife when he was working in Australia.
- Here, the clause, when he was working in Australia acts as the adverbial of the whole complex sentence. (In the complex sentence, Harry’s first wife believed he was an honest man the clause, he was an honest man acts as the object.)