Writers often overuse and misuse semicolons. Semicolons have essentially two functions:
1. To separate closely related independent clauses that are not connected by conjunctions
2. To replace commas when the items to be kept apart have internal commas
The semicolons in these sentences separate two independent clauses. An independent clause can stand on its own.
If both clauses aren't independent, then some other form of punctuation is required.
She went to Europe to find herself; she found a husband instead.
Students exhaust themselves during exam week; many of them stay up for days.
These semicolons separate items in a list that already has internal commas:
This is apparent in Chris Rock's new DVD Kill the Messenger, which combines three shows from his international tour: New York; London, England; and Johannesburg, South Africa.
A semicolon is not needed for a long list of items if that list has no internal commas. The reason is that the question of What is long? is open to interpretation. So these two lists (the first a run-in list and the second a bulleted list) are correct with just commas to separate the series of items:
Under this test, a government practice is unconstitutional if it lacks a secular purpose, its primary effect either advances or inhibits religion, or it excessively entangles government with religion.
Through expert instruction, coaching tips, and one-of-a-kind insights into the sport, you'll learn to
" develop the individual offensive and defensive skills of the game,
" master the specialty skills of field players and goalkeepers,
" train like a champion with sport-specific conditioning drills,
" sharpen individual and team execution with situational drills, and
" maximize potential by making the most out of practice time.
Lists of more than two independent clauses should be separated by commas when the second and subsequent clauses complete the thought expressed in the first clause:
We saw it, we liked it, we bought it.
After a one-word introduction or a short interjection, use a comma:
Yes, we can.
Sure, that'll work.
Okay, I'll do it.
Fine, she's not your girlfriend.
Well, no, I never said that.
Oh, my, that cat is fat!
Some writers use semicolons when they should use colons. The semicolon in this example should be a colon because
the second clause describes the statement in the first clause and because the second clause is subordinate (that
is, it can't stand on its own):
There will be a few new pieces of art; a few that we're redrawing and some that we're pulling from other HK books.
And this semcicolon should be a comma because the first clause is independent and the second clause is subordinate:
I thought for a while that his distractibility and irritability were just products of these; that everyone in high tech was getting wigged out by all this stimulation.