Some writers are naturally adept at the mechanics of writing. Others have to work at it because their strength lies in the art of storytelling. Still, knowing how to write a grammatically correct sentence — and knowing when it's okay to bend or even break those grammar rules — is a necessary skill for an author … especially if she hopes to get published.

Before you can write a good romance novel, you need to know how to write a good sentence. Understanding what makes a sentence complete — and most important, what makes a sentence incomplete — is the first step.

Simply put, sentences are a word, or a string of words, that do one of the following three things:

• Make a statement, such as Mark kissed Helen.

• Ask a question, such as Who kissed Helen?

• Issue a command or a wish, such as Shut up and kiss me!

For a sentence to be complete, it must have a subject and a predicate. The subject is a noun or pronoun that represents the person, place, or thing at the center of the sentence. The sentence also must have a predicate, which is a verb (the words in the sentence that describe existence, action, or occurrence) and its various modifiers. The subject performs the action described by the predicate. For example, in the sentence, Mark kissed Helen, Mark is the subject, kissed is the verb, and Helen is the object, or recipient, of Mark's kiss.

One of the most common grammar mistakes involves subject-verb agreement. This occurs when the verb tense being used doesn't match the subject. Grammar rules state that singular subjects require singular verbs. Conversely, plural subjects require plural verbs. Mistakes happen when a writer pairs a singular subject with a plural verb, or vice versa.

For example, Tom walk down the hall would be incorrect because the singular subject, Tom, requires a singular verb form of “walk,” which in this case is walks. The correct sentence would be Tom walks down the hall or The men walk down the hall.

Usually, if the subject is a proper name or a pronoun, it's easy to choose the right verb form. (Tom is. He was.) Not so for a place or thing. Remember, places, such as cities and states, are singular but things can be either. To figure out whether your non-proper name subject needs a singular or plural verb, try substituting the words he or she for a singular subject and they for a plural subject. When you read the sentence aloud, the correct verb choice should be clear.