A sentence is a group of words beginning with a capital letter and ending with a full stop/period, exclamation mark or question mark.
It is the written equivalent of an utterance.
My name is Conan.
Is July going to be hot here?
There are a number of different sentence types in English and we use them for different purposes.
To give information we use statements:
I worked in China.
The sea is rough today.
In these examples above the statements were positive but we can also make negative statements:
I’ve never worked in Japan.
It isn’t warm enough to swim today.
See the main article, Statements.
We use questions to ask for information:
Have you read all the Harry Potter books?
Does he really know how to speak Vietnamese?
See the main article, Questions.
When we want to give an order, we use an imperative sentence:
Get out now!
See the main article, Imperatives,
We use exclamations when we are surprised or angry:
What a load of rubbish!
The longest sentence in the English language is apparently from Jonathan Coe’s novel, The Rotter’s Club. It is 13,955 words long which is far longer than the famous long sentences of James Joyce’s Ulysses – Molly’s soliloquy, which contains 8 sentences, the longest of which is 4,391 words long.
Meanwhile the shortest sentence in English can be just one word in length.
– Who’s pen is this?
And finally a sentence does not have to make sense. Noam Chomsky famously gives an example of a sentence which is grammatically sound but is semantically nonsense:
Colorless green ideas sleep furiously.