Introductory clauses also require a comma. grammar checkers usually don’t
notice when you forget to use a comma after an introductory clause. As the name
implies, these introduce a sentence. They do not stand on their own as sentences,
and they can modify the overall meaning of the sentence. They serve to provide contextual
or background information to give more detail to the primary clause of the sentence.
Although they haven’t slept in days, scientists are excited about exploring
Mars.
Everything before the comma in this sentence is introductory. Although the introductory
clause has its own verb and subject, it cannot stand on its own because of the adverb
"although."Words like although, since, because, after, though, until, as,
before, etc. indicate that you have an introductory clause and need to use
a comma.
Despite a lack of sleep and nutritious food, scientists feel excited about
exploring Mars.
This sentence may seem clearer. The introductory clause cannot make a sentence and
serves only the purpose of providing background information.
There are other forms of introductory clauses. Most of them require a comma, but
a few do not.While precise guidelines vary, most of them agree that introductory
clauses fewer than five words do not require a comma unless the sentence
would sound confusing without a comma. If you cannot tell whether or not the sentence
is confusing without a comma after the introductory clause, then it probably is
confusing, so use the comma. If you have doubts about comma usage other than in
introductory clauses opt for not using a comma.Most people add too many commas rather
than too few.
Lists require commas.The rules about using commas in lists are very simple,
but grammar checkers fail to catch listing errors. A correct list looks like this:
The performer swallows knives, forks, fire, and glass.
Notice a comma does precede "and." (We have changed this preference.)
Traditional English grammar puts a comma before "and" in every
list, but it has become a modern rule not to use a comma prior to "and"
in a simple list. In more complex lists, modern usage still indicates inserting
a comma prior to "and." This is because it can be confusing as to whether
or not the items are separated. Consider the following two sentences:
Pain, suffering, loss of income and
medical bills are examples of damages.
Pain, suffering, loss of income, and medical bills are examples of damages.
In the first sentence, it could mean a loss of income as well as a loss of medical
bills, which doesn't make any sense and is potentially confusing. In the second
sentence, it is clear that "loss" refers only to income. For purposes of
clarity, use the traditional method of inserting a comma prior to "and"
and "or" in a list of items.
An incorrect list looks like this:
The performer swallows knives forks,
fire, and glass.
This sentence should have a comma after "knives," but the grammar checker
may not notice.
Commas also separate non-essential clauses from the sentence. As the term
implies, non-essential refers to a section of the sentence that can be removed without
turning the sentence into a fragment. Similar to introductory
clauses, non-essentials add detail to the sentence. For example:
The politician, who had been acquitted many times before, was found innocent.
The trick to finding a non-essential clause lies in breaking the sentence apart.
Without the non-essential clause, this sentence reads:
The politician was found innocent.
A grammar checker can sometimes find when you add a non-essential clause but forget
the commas:
The politician who had been acquitted
many times before, was found innocent.
If you omit both commas, the grammar checker may not find it:
The politician who had been acquitted many times before was
found innocent.
Coordinated Adjectives and Commas
Coordinated adjectives refers to when a group of adjectives are used to modify the
same noun; for example, “the little old lady” or “that tall, distinguished
gentleman.” As the previous example shows, when to use commas to separate
the adjectives can be confusing.
As always, there is a general rule to help you decide. If you can place the
word “and” or “but” in between the adjectives, then you
should use a comma there.
As in the two examples above, it is more common that one would say, “That
tall and distinguished gentleman,” than “The little and old lady.”
Likewise, you probably wouldn’t say, “I live in a little and purple
house,” so you don’t use commas: I live in a little purple house.
But you would write, “I live in a very old and run-down house”; so you
write, “I live in a very old, run-down house.”
It may seem like semantics, which of course it is, but as you are in the middle
of examples, applying the rule will seem more useful.
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