A fused sentence is when two or more separate sentences have been put together in a way that creates one grammatically incorrect sentence.
It’s not about the length of the sentence; it’s about whether or not there’s too much in the sentence, whether two sentences have been incorrectly joined as one. Here are some examples:
*I’m hungry I didn’t eat.
*I am you’re not.
*I love school English is my favourite subject.
*We can it’s easy.
*He works really hard he’s great at it.
So what are the ways that we can ‘join’ sentences?
There are three ways. Be aware that not every way works in every situation: it depends on the situation.
With a full stop. (Although it doesn’t seem like it, this is a way of ‘joining’ sentences because it’s how we put them together in a sequence.)
With a coordinating conjunction - a FANBOYS (for, and, nor, but, or, yet, so).
With a colon (:) or semicolon (;). But we use these in quite specific situations, so read here for more information.
In a comma splice sentence, two or more separate sentences have been put together using a comma in a way that creates one grammatically incorrect sentence.
Comma splices is a very common issue. In fact, it’s probably even more common than fused sentences.
Part of the problem is that most people have been taught something that is untrue when it comes to commas:
Commas are not used whenever we pause or take a breath.
Even though many of us have been taught to use a comma to signal when we ‘take a breath’ (by actually breathing in or by just pausing), this is wrong.
This single mis-learnt fact is the cause of almost every comma splice that every student writes.
Commas aren’t actually related to breathing. (And their relationship to pausing is quite loose, too.)
Commas are used for one thing: to add additional information that fits within the same sentence.
In other words, commas are used to:
Separate items in lists of verbs, nouns, adjectives, adverbs (and occasionally prepositions and pronouns)
Add extra information to a sentence - as long as the thing that’s added couldn’t form its own sentence.
Another way of thinking about commas is to understand that they’re quite a ‘weak’ piece of punctuation: they’re only strong enough to work within sentences and not across sentences.
The way that you fix a comma splice is the same way that you fix a fused sentence.
Using a full stop
Using a coordinating conjunction - a FANBOYS (for, and, nor, but, or, yet, so)
The trick is to know when the comma is adding information (correctly) and when it’s trying to join two sentences (incorrectly).