Sentences

Grammar is about how sentences are constructed. Sentences, however, are not easy to define. One traditional definition is that a sentence is ‘the expression of a complete thought or idea’. However, it is not difficult to think of sentences that are grammatically correct, but which do not fit this definition. For example, it would be difficult to explain the complete thought or idea in:

Is that it?

Equally, there are plenty of non-sentences that do seem to express a complete thought or idea. For example:

DANGER LIVE CURRENT

or

God

And then again, you have to remember that it is perfectly possible to construct sentences that are grammatically acceptable, but which don’t make a lot of sense. Chomsky’s famous example of this was

Colorless green ideas sleep furiously.

So it is better to define a sentence in formal terms as a grammatical unit that consists of one or more finite clauses.

Sentence types

There are four types of sentence:

• declarative
  These are sentences normally used to make statements such as Elephants are dangerous.
• interrogative
  These are normally used to ask questions like Are elephants dangerous? or What are those elephants doing?
• imperative
  These are normally used to make commands, orders, and requests, like Look at that elephant!
• exclamative
  These are used to make exclamations of various kinds such as How charming that little baby elephant is!

Each of these sentence types has a distinctive word order. Declarative sentences are the most common and the other types can be built up from them.

What next?

The next section introduces the seven basic clause patterns of English. Each one is based on a simple sentence: a sentence that contains only one clause.

©John Seely 2008