RULES FOR SEMICOLONS
1. Use a semicolon to link two independent clauses.
To give a good party, you must consider the lighting; no one feels comfortable under the bright glare of fluorescent lights.
Note that the two clauses are connected in thought, but are each independent grammatically. A comma with a conjunction can stand in place of the semicolon, like this:
To give a good party, you must consider the lighting, since no one feels comfortable under the bright glare of fluorescent lights.
2. Use a semicolon to separate elements in a list if the elements are long – or if the elements themselves have commas in them.
To get completely ready for your party, you should clean your house; make sure your old, decrepit stereo works; prepare a lot of delicious, strange food; and expect odd, antisocial, and frivolous behavior on the part of your guests.
3. Unlike commas, semicolons belong outside quotation marks.
One man at the party sat in a corner and read “The Adventures of Bob”; he may have been shy, or he may have found “The Adventures of Bob” too exciting to put down.