Commas are probably the most frequently used piece of
punctuation, so it is not surprising that comma errors often
cause writers more problems than any other type of punctuation
errors. But the solution to these problems is not difficult as
most comma errors can be eliminated if writers will learn just
seven rules: Use commas to separate items in a series. Example:
I bought milk, eggs, and cheese. Comment: A series must contain
at least three items. Some people have been taught that the
comma before the “and“ is optional, but when in doubt about what
your audience finds acceptable, you should use the comma before
“and.” Use commas to set off introductory material. Example:
After I went to the store, I went to visit Mrs. Smith. Comment:
One way to identify introductory material is to find the subject
of the sentence and then note whether or not there is anything
to the LEFT of the subject. If so, place a comma at the end of
the material, just before the subject. “Subject” in this case
refers to the grammatical