Have you had an assignment returned and wondered why your instructor has marked up your grammar and spelling? This isn't an English or Rhetoric class, right?

Rules of grammar do not exist to make your life difficult, but to help us to clearly understand one another. Bad grammar clouds your description or argument, and makes it difficult for your instructor to evaluate how well you completed the assignment. No matter how good your ideas are, you must communicate them clearly if you want to do well.

This isn't just a skill you need in college. Imagine turning in an application for a new job, a report to your boss, a pitch for funding, or giving a presentation where your grammar is confused. You'll make a bad impression. You may be a genius, but if others cannot easily understand your point of view it becomes easy for them to brush it aside.


We've gathered together some of the most common grammatical errors in our handout Tips for Writing Good. Try spotting the mistake in each sentence and correcting it.

If you can't find the mistake, or want more information on why a particular sentence was incorrect, check out our solutions page, Tips for Writing Well. This page also defines problems your instructors might have identified in your writing, such as passive voice, shifting tenses, or run-on sentences.

We've created a page that provides information to help you understand Passive and Active Voice in your writing.

Our handout Commas, Commas, Commas offers advice on how to use commas effectively in your writing.

The Online Grammar Slammer also offers help on a variety of grammar questions.