what is a sentence

In order to improve my writing, I found information about making sentences.

This information was very useful.

A written sentence should have certain characteristics:

a capital letter at the beginning
a full-stop at the end
a subject (who or what the sentence is about)
a verb (that tells you what's happening)
and, finally, many people say that it should express 'a single thought'

There are a few other helpful points to remember about a sentence:

a sentence can be long or short
it can be very simple or very complex
a sentence can be broken up with commas, semi-colons, colons, dashes and so on

Have a look at the examples below. Are they sentences? If so, what type of sentences?

This bill is now due for payment.
Do you support experiments on animals?
Do not go beyond this point.
Blair must go!

No doubt you will recognise that one is a statement, one a question; one is an instruction (or command) and one is an exclamation. We can subdivide sentences into many different types but perhaps the most important point to consider at this stage is this: can we be sure that a collection of words is actually a sentence?

Have a look at the examples below. Are they all sentences or are they parts of sentences i.e. fragments?

Task

Are these sentences? Decide for yourself and then check the notes at the end of this unit

Did the secretary tell you?
What a noise they were making!
And close the door when you go out!
But he never heard the reply.
But the summer was lovely that year.
Because I was doing your shopping.
Because of the heavy rain this year, Wimbledon has been postponed.
A long dark shape, with a short white tail.
Place your baggage here.
That's amazing!
The central character represents darkness and evil that can be found in our society she exhibits no kindness or generosity of any sort.
Foreign direct investment can be an effective and quick way for a developing country to build up its locally-based companies however it is not the only way.

Notes on Task
Did the secretary tell you? It's a question and it's also a sentence.
What a noise they were making! It's an exclamation and it's a sentence.
And close the door when you go out! It's a single thought so in that way it's a sentence. It's certainly a sentence without the 'and' but, as it stands, it's not a very good one because it begins with the linking word 'and' which is not a very suitable word to start a sentence.
But he never heard the reply. Again, take away the 'but' and there is no question, but the word 'but' is a linking word and not very suitable to start a sentence, so it's not a very good sentence.
But the summer was lovely that year. This is rather a poetic sentence even if it does start with 'but'.
Because I was doing your shopping. 'Because' is another word that you have to be careful about when starting sentences. This would not be regarded as a good written sentence as it should be linked to a clause before the word' because'.
Because of the heavy rain this year, Wimbledon has been postponed. Here the use of 'because' is acceptable as it provides a reason for the postponement.
A long dark shape, with a short white tail. Definitely not a sentence because it doesn't have a verb.
Place your baggage here. An instruction and a sentence.
That's amazing! An exclamation, and a very short sentence.
The central character represents darkness and evil that can be found in our society she exhibits no kindness or generosity of any sort. This section should be a separate sentence: She exhibits no kindness or generosity of any sort
Foreign direct investment can be an effective and quick way for a developing country to build up its locally-based companies however it is not the only way. This part should be a separate sentence: However, it is not the only way.