The grammar mistakes people make most often include a missing comma after an introductory element, mixing up its and it's, vague pronouns, and confusing similar words. Split infinitives are on many lists too, although they are a matter of style rather than a real mistake. Here is how to spot and avoid each one.
If you want to be seen as a credible writer, you need to know your grammar. Some people don't even notice when they make a mistake, because some errors are so common. You see them every day, and sooner or later you pick up the bad habit yourself.
1. A missing comma after an introductory element
Put a comma after an introductory clause or a long introductory phrase. Without it, readers can easily take the wrong words together.
- Incorrect: When we called Karen didn't answer.
- Correct: When we called, Karen didn't answer.
Without the comma, the sentence first seems to say that we called Karen. After a short introductory phrase, the comma is optional, but it never hurts: After the party, Karen ignored my calls. For more, see correct comma usage.
2. Its or it's
Its shows possession, while it's is a contraction of "it is" or "it has".
- Incorrect: The smart robot is fixing it's own mistakes.
- Correct: The smart robot is fixing its own mistakes.
The post on it's vs. its explains the difference in detail.
3. A vague pronoun reference
A pronoun is a word that takes the place of a noun or a noun phrase, such as she, it, or they. A vague pronoun reference is a common mistake, not only in fiction but also in nonfiction and even in the news.
Readers may be able to work out who a pronoun refers to, but you should not make them guess.
- Incorrect: When Cherry finally found Marie at the station, she was overjoyed. (Who was overjoyed, Cherry or Marie?)
- Correct: Cherry was overjoyed when she finally found Marie at the station.
4. The wrong word
Some words are easy to confuse. They sound alike, look alike, or both, and even experienced writers sometimes mix them up. To make matters worse, English has hundreds of such pairs.
Here is one example:
- Incorrect: We need to consult the doctors to investigate this case farther.
- Correct: We need to consult the doctors to investigate this case further.
Farther is for physical distance, while further also means "more" or "to a greater degree". The post on farther vs. further has more examples.
Here is another one:
- Incorrect in American English: Please remind me to bath the cat this afternoon.
- Correct: Please remind me to bathe the cat this afternoon.
In American English, bath is the noun and bathe is the verb. British English also uses bath as a verb for washing someone in a bath, so there both sentences are fine.
5. Split infinitives
A split infinitive is an adverb placed between to and the verb, as in "to quickly remove". Split infinitives are common in speech and writing, and people often use them to stress how something is done. Strictly speaking, they are not a grammar mistake: most modern style guides and dictionaries accept them. Some readers and teachers still frown on them, though, so in formal writing you may want to move the adverb.
- Split: Jamie uses baking soda to quickly remove the stain on the carpet.
- Not split: Jamie uses baking soda to remove the stain on the carpet quickly.
Don't force it, though. If moving the adverb makes a sentence clumsy or changes its meaning, keep the split infinitive.
Check before you hand it in
In formal writing, such as an essay, these mistakes can cost you dearly. Always double-check your grammar and spelling before you hand in your work. Reading your text aloud is an excellent way to catch mistakes. The Spell Checker also points out spelling and grammar mistakes that you might otherwise miss.