Sentence Fragments and Run-on sentences

[Clevernick]

This is the other thing that, in my experience, many writers have trouble with, even the pros at times. The following rules may be broken within speech, but not in narrative, until you have sold at least 500,000 copies of a book. Then you can tell me when exceptions may be made.

1. A sentence contains one verb. No less. If it's less, add one. If more, see rules three and four. So these are wrong:

What an incredible day! (No verb, so not a sentence. Allowed only in speech.)
She went to the liquor store and she bought some Frangelico and she drove home and she drank herself into a stupor and she woke up hung over. (Too many verbs; really a bunch of sentences.)

2. Participles, such as "eating", "lying", "writhing", are not, by themselves, verbs!

Lying beside her on the bed. (Not a sentence because "lying" isn't a verb)
The robot lying beside her on the bed. (Still the same problem)
The robot was lying beside her on the bed. (Better)

3. Commas do not join sentences. Join two closely-related sentences with a semicolon. (If it would make sense to use a period, it does NOT make sense to use a comma.)

Commas do not join sentences, join two closely-related sentences with a semicolon. (Wrong)
Commas do not join sentences; join two closely-related sentences with a semicolon. (Better)

Exceptions (very short sentences, etc) only as in Strunk and White: http://www.bartleby.com/141/strunk.html

4. Conjunctions (and, but, or) may join related sentences, but use precision.

"It was a sunny day and she screamed." is not a good use of a conjunction. Choose your joining method with care to help the reader understand.

My sub really hates this particular whip, I like it. (wrong)
My sub really hates this particular whip and I like it. (poor)
My sub really hates this particular whip; I like it. (correct but ambiguous)
My sub really hates this particular whip but I like it. (good - relationship explained)
My sub really hates this particular whip; that's why I like it. (excellent)

And a wonderful example from Douglas Hofstadter -- Choose your conjunctions with care -- you can make truth into absurdity otherwise:

Politicians lie. Cast iron sinks. (True)
Politicians lie and cast iron sinks. (True but poorly chosen conjunction)
Politicians lie in cast iron sinks. (O RLY?)

5. Memorize Strunk chapter II (it's very short!) and then re-read the above.
Strunk chapter II again: http://www.bartleby.com/141/strunk.html

Some of Strunk's rules from 1918, like the use of serial commas, are becoming more flexible lately. Still you will do much better knowing these than not knowing them. They are the anchor; without them you are adrift. Know them and build.