Verbs are words we use to name action, condition, or existence. They have five features we can use to express certain aspects of reality and the communication situation: number, person, voice, mood, and tense (or time frame). In this handout we will be dealing only with tense, specifically with the responsibility we have as writers and speakers to use tense shifts effectively and to avoid unnecessary tense shifts.
Tense is the feature of verbs that allows us to express time—both period and duration. In other words we can use verbs to set a time period for an action—whether it happened (past tense), happens now (present tense) or will happen (future).
I cooked the spaghetti. ( past)
I cook the spaghetti. (present)
I will cook the spaghetti. (future)
But verbs can also indicate whether the action is ongoing (was happening, is happening, or will have been happening) or has been completed (has happened, had happened, or will have happened) at a certain time.
I was cooking the spaghetti. (past progressive—the action was ongoing during the past period we are talking about)
I am cooking the spaghetti. (present progressive—the action is ongoing, even as we speak)
I will be cooking the spaghetti. (the action will be ongoing during some future time frame)
I had cooked the spaghetti. (past perfect—the action was completed before a specified time in the past)
I have cooked the spaghetti. (present perfect—the action was completed before the present time)
I will have cooked the spaghetti. (future perfect)—the action will be completed by specified time in the future.
With these capabilities, verbs allow us to order events logically in time, so we can speak not only about actions in the past, but also about actions that are ongoing during the past or about actions that were completed before a specified time in the more recent past. In other words we can show a past that has a past or a future that has an ongoing action in it. Consider the following sentence:
I had finished preparing the salad, so I dredged the chicken in flour and heated the oil.
We actually have two time periods in this sentence—a simple past (I dredged the chicken in flour and heated the oil) and a past time before the simple past, in which I had completed an action (I had finished preparing the salad).
The example sentence required us to shift tenses in the middle of the sentence in order to provide an accurate and logical sequence of events for our readers. We shifted tenses by changing the verb forms from a past perfect form (had prepared) to show the past of the past in the first clause to a simple past form (dredged and heated) in the second clause.
The key point to remember is to use tense shifts only when you have a reason to move your audience to a different time frame.
For instance, in the following sentence there is no reason for the tense shift.
Last year Harry took three college classes, managed the tutoring center, and pays for his car.
This example sentence causes us to pause on the brink of confusion because it has shifted tenses for no reason. Its primary tense is past (took and managed). There is no valid reason to suddenly jump into the present tense (pays), so we are taken aback for a moment, and the sentence sounds very awkward to us.
You can test your understanding of this handout by completing Student Success Center exercises available here.