No matter how many times we write "passive" in their margins students just don't recognize passive voice. This might be because asking oneself, "Does the subject of this sentence perform the action of the sentence?" is a clunky way of reviewing a draft. Students need a quick and easy way to identify passive sentences.
"To be" verbs are an easy-to-spot clue
"The man was hit by a car" is a passive sentence while "A car hit the man" is an active sentence. The "was" in the first sentence makes it passive and by removing it and revising the sentence accordingly, the sentence becomes active.
While not every "to be" verb indicates a passive sentence, checking a text for "to be" verbs and eliminating as many as possible is a simple, straightforward, easy-to-remember exercise that solves a great deal of passive voice problems.
This lesson has two parts, and is best spread over two days (if you have 1hr 15min classes) or an entire three-hour class.
Part 1: Instructor-led revision
For the first part of this lesson, review the definition of passive voice and the "to be" verbs handout. Next, project a sample essay on the board and use the Control+F function to find and highlight every "to be" verb in the text. Start with the most commonly used verbs, like is and was. As a class, read the essay sentence by sentence, identify whether each highlighted verb is problematic, and have students suggest ideas for revision. Try to revise at east two pages so the class gets a feel for the exercise.
Part 2: Student-led revision
Have the students pair up, exchange papers, highlight every "to be" verb they find in their classmate's paper, and hand them back. There will likely be highlighting covering the page, which should shock them. (This is what you want to happen.) Next, have the pair work together and revise away as many "to be" verbs as possible and appropriate.
Some students attempt to eliminate every "to be" verb, even when they shouldn't
Anxious, straight-A students will embrace this straight-forward exercise because it seems like an unambiguous path to an A. Rather than use their own judgment (which is hard) some decide to eliminate every "to be" verb from their essay. Accomplishing this leads to convoluted and weird sentences. Sometimes, that "to be" verb is the right verb for the job.
Telling these students to relax, that they don't have to eliminate every single one, results in questions like, "What percentage of 'to verbs' should we get rid of?" "How many points will be taken off for each 'to be' verb in the paper?" and "What is the maximum number of 'to be' verbs allowed in our essay?" This is what rubrics do to them.