Types of comma, and rules surrounding them

The isolating/bracketing commas:

The most common type of commas and they are used to show a weak interruption in the sentence, something we could put in brackets hence the name. They usually occur in pairs although sometimes one of them won’t show.

He was, I thought at the time, a decent enough person.
I never realised, however, how much effort it will take to go to University.
Alfred Charles Gimson, born in 1917, was an English phonetician.

The easiest way to check whether you need commas is to imagine a given sentence without the interruption you’re trying to mark. If it still makes sense – commas should be there e.g. He was a decent enough person is still a sentence even after removing I thought at the time.

A listing comma:

It can be replaced by and or or:

I like eating bananas, watermelons and kiwis. / I like eating bananas and watermelons and kiwis.
I will go to Italy, Spain or Portugal. / I will go to Italy or Spain or Portugal.

A joining comma:

It is used to join two complete sentences into one and is always followed by and, or, but, while and yet.

I went to college, and my husband did as well.
I must have forgotten about my homework, or there was no homework at all.
I loved him, but he turned out to be a psychopath.
She was a good and loyal person, while his new girlfriend is a lying cheat.
The train was running, yet I felt I was stuck in the same place.

A gapping comma:

It is used when omitting words already used in a sentence in order to avoid repetition.

I dyed my hair black, and my sister, red.

Bear in mind the comma before and is a joining comma, whereas the one before red is a gapping comma (used instead of repeating has dyed her hair).

The Importance of Spaces

You can’t see them, but you know they’re there. I’m talking about spaces. There are some pairs of words that can be used joined together as one word or kept separate with a space. The distinction can be very subtle or very marked. Here are some of the most common examples.


every day & everyday

I go to the gym every day
(Here every day is an adverb meaning on a daily basis).
I have a tuxedo for special events as well as my everyday suits for work
(Here everyday is an adjective that means ordinary, not special)
Going to the gym is an everyday occurence for me
(Here everyday is again used as an adjective, but this time literally meaning every day or pretty much every day anyway)

everyone & every one

Everyone deserves a treat now and again
(Everyone means all the people, everybody can often be substituted for everyone)
Make sure you check that every one of those envelopes has a signed cheque inside it
(We could have used all here, using the phrase every one emphasises that we definitely don’t want any missed out)

all together & altogether

I’m not altogether sure about the meaning of this word
(In this context altogether means completely or entirely, either of these words could be used instead)
I’ll do the presentation when we are all together in the same room
(All together means in the same place at the same time)

into/in to

Put the ice cream into the freezer
(Here into is used to emphasise the motion of putting something inside something else)
Governments rarely give in to ransom demands
Johnny handed his homework in to the teacher
(In these examples giving in and handing in are phrasal verbs so we need to put a space before to)

all right/alright

Alright is the less formal spelling of “all right” (more of a British-English thing)
How are you? I’m alright thanks (means I am ok, nothing much to complain about)
How was the film? It was alright (in this case it means passable, in the sense of it being average, nothing special)
Then there is the use of all right as two discrete words...
Make sure the figures are all right (i.e. correct) before you send the quotation to the customer.

all ready/already

I already ate (Already means you have done something, usually, but not always, in the recent past)
When you’re all ready I shall begin (Here all just means everyone present)

As is often the case in English if you’re not sure of something avoid using it. If a dictionary isn’t available for you to check something then you may well find a way of expressing what you want to say using words that you already know the meaning of.