语言教学 | 普渡大学写作教学系列General Writing 74-Grammar(15)：Verb Tenses(2)

提示：点击上方"英语写作教学与研究"免费关注哦

征稿：二语写作

Verb Tense Consistency

Throughout this document, example sentences with nonstandard or inconsistent usage have verbs in red.

Controlling shifts in verb tense

Writing often involves telling stories. Sometimes we narrate a story as our main purpose in writing; sometimes we include brief anecdotes or hypothetical scenarios as illustrations or reference points in an essay.

Even an essay that does not explicitly tell a story involves implied time frames for the actions discussed and states described. Changes in verb tense help readers understand the temporal relationships among various narrated events. But unnecessary or inconsistent shifts in tense can cause confusion.

Generally, writers maintain one tense for the main discourse and indicate changes in time frame by changing tense relative to that primary tense, which is usually either simple past or simple present. Even apparently non-narrative writing should employ verb tenses consistently and clearly.

General guideline: Do not shift from one tense to another if the time frame for each action or state is the same.

Examples:

1. The instructor explains the diagram to students who asked questions during the lecture.

Explains is present tense, referring to a current state; asked is past, but should be present ( ask ) because the students are currently continuing to ask questions during the lecture period.

CORRECTED: The instructor explains the diagram to students who ask questions during the lecture.

2. About noon the sky darkened, a breeze sprang up, and a low rumble announces the approaching storm.

Darkened and sprang up are past tense verbs; announces is present but should be past (announced) to maintain consistency within the time frame.

CORRECTED: About noon the sky darkened, a breeze sprang up, and a low rumble announced the approaching storm.

3. Yesterday we walk to school but later rode the bus home.

Walk is present tense but should be past to maintain consistency within the time frame (yesterday); rode is past, referring to an action completed before the current time frame.

CORRECTED: Yesterday we walked to school but later rode the bus home.

General guideline: Do shift tense to indicate a change in time frame from one action or state to another.

Examples:

1. The children love their new tree house, which they built themselves.

Love is present tense, referring to a current state (they still love it now;) built is past, referring to an action completed before the current time frame (they are not still building it.)

2. Before they even began deliberations, many jury members had reached a verdict.

Began is past tense, referring to an action completed before the current time frame; had reached is past perfect, referring to action from a time frame before that of another past event (the action of reaching was completed before the action of beginning.)

3. Workers are installing extra loudspeakers because the music in tonight's concert will need amplification.

Are installing is present progressive, referring to an ongoing action in the current time frame (the workers are still installing, and have not finished;) will need is future, referring to action expected to begin after the current time frame (the concert will start in the future, and that's when it will need amplification.)

Controlling shifts in a paragraph or essay

General guideline: Establish a primary tense for the main discourse, and use occasional shifts to other tenses to indicate changes in time frame.

Hints:

• Rely on past tense to narrate events and to refer to an author or an author's ideas as historical entities (biographical information about a historical figure or narration of developments in an author's ideas over time).

• Use present tense to state facts, to refer to perpetual or habitual actions, and to discuss your own ideas or those expressed by an author in a particular work. Also use present tense to describe action in a literary work, movie, or other fictional narrative. Occasionally, for dramatic effect, you may wish to narrate an event in present tense as though it were happening now. If you do, use present tense consistently throughout the narrative, making shifts only where appropriate.

• Future action may be expressed in a variety of ways, including the use of will, shall, is going to, are about to, tomorrow and other adverbs of time, and a wide range of contextual cues.

Using other tenses in conjunction with simple tenses

It is not always easy (or especially helpful) to try to distinguish perfect and/or progressive tenses from simple ones in isolation, for example, the difference between simple past progressive ("She was eating an apple") and present perfect progressive ("She has been eating an apple"). Distinguishing these sentences in isolation is possible, but the differences between them make clear sense only in the context of other sentences since the time-distinctions suggested by different tenses are relative to the time frame implied by the verb tenses in surrounding sentences or clauses.

Example 1: Simple past narration with perfect and progressive elements

On the day in question...

By the time Tom noticed the doorbell, it had already rung three times. As usual, he had been listening to loud music on his stereo. He turned the stereo down and stood up to answer the door. An old man was standing on the steps. The man began to speak slowly, asking for directions.

In this example, the progressive verbs had been listening and was standing suggest action underway at the time some other action took place. The stereo-listening was underway when the doorbell rang. The standing on the steps was underway when the door was opened. The past perfect progressive verb had been listening suggests action that began in the time frame prior to the main narrative time frame and that was still underway as another action began.

If the primary narration is in the present tense, then the present progressive or present perfect progressive is used to indicate action that is or has been underway as some other action begins. This narrative style might be used to describe a scene from a novel, movie, or play, since action in fictional narratives is conventionally treated as always present. For example, we refer to the scene in Hamlet in which the prince first speaks (present) to the ghost of his dead father or the final scene in Spike Lee's Do the Right Thing, which takes place (present) the day after Mookie has smashed (present perfect) the pizzeria window. If the example narrative above were a scene in a play, movie, or novel, it might appear as follows.

Example 2: Simple present narration with perfect and progressive elements

In this scene...

By the time Tom notices the doorbell, it has already rung three times. As usual, he has been listening to loud music on his stereo. He turns the stereo down and stands up to answer the door. An old man is standing on the steps. The man begins to speak slowly, asking for directions.

In this example as in the first one, the progressive verbs has been listening and is standing indicate action underway as some other action takes place. The present perfect progressive verb has been listening suggests action that began in the time frame prior to the main narrative time frame and that is still underway as another action begins. The remaining tense relationships parallel those in the first example.

In all of these cases, the progressive or -ing part of the verb merely indicates ongoing action, that is, action underway as another action occurs. The general comments about tense relationships apply to simple and perfect tenses, regardless of whether there is a progressive element involved.

It is possible to imagine a narrative based on a future time frame as well, for example, the predictions of a psychic or futurist. If the example narrative above were spoken by a psychic, it might appear as follows.

Example 3: Simple future narration with perfect and progressive elements

Sometime in the future...

By the time Tom notices the doorbell, it will have already rung three times. As usual, he will have been listening to loud music on his stereo. He will turn the stereo down and will stand up to answer the door. An old man will be standing on the steps. The man will begin to speak slowly, asking for directions.

In this example as in the first two, the progressive verbs will have been listening and will be standing indicate ongoing action. The future perfect progressive verb will have been listening suggests action that will begin in the time frame prior to the main narrative time frame and that will still be underway when another action begins. The verb notices here is in present-tense form, but the rest of the sentence and the full context of the narrative cue us to understand that it refers to future time. The remaining tense relationships parallel those in the first two examples.

General guidelines for use of perfect tenses

In general the use of perfect tenses is determined by their relationship to the tense of the primary narration. If the primary narration is in simple past, then action initiated before the time frame of the primary narration is described in past perfect. If the primary narration is in simple present, then action initiated before the time frame of the primary narration is described in present perfect. If the primary narration is in simple future, then action initiated before the time frame of the primary narration is described in future perfect.

Past primary narration corresponds to Past Perfect (had + past participle) for earlier time frames

Present primary narration corresponds to Present Perfect (has or have + past participle) for earlier time frames

Future primary narration corresponds to Future Perfect (will have + past participle) for earlier time frames

The present perfect is also used to narrate action that began in real life in the past but is not completed, that is, may continue or may be repeated in the present or future. For example: "I have run in four marathons" (implication: "so far... I may run in others"). This usage is distinct from the simple past, which is used for action that was completed in the past without possible continuation or repetition in the present or future. For example: "Before injuring my leg, I ran in four marathons" (implication: "My injury prevents me from running in any more marathons").

Time-orienting words and phrases like before, after, by the time, and others—when used to relate two or more actions in time—can be good indicators of the need for a perfect-tense verb in a sentence.

• By the time the senator finished (past) his speech, the audience had lost (past perfect) interest.

• By the time the senator finishes (present: habitual action) his speech, the audience has lost (present perfect) interest.

• By the time the senator finishes (present: suggesting future time) his speech, the audience will have lost (future perfect) interest.

• After everyone had finished (past perfect) the main course, we offered (past) our guests dessert.

• After everyone has finished (present perfect) the main course, we offer (present: habitual action) our guests dessert.

• After everyone has finished (present perfect) the main course, we will offer (future: specific one-time action) our guests dessert.

• Long before the sun rose (past), the birds had arrived (past perfect) at the feeder.

• Long before the sun rises (present: habitual action), the birds have arrived (present perfect) at the feeder.

• Long before the sun rises (present: suggesting future time), the birds will have arrived (future perfect) at the feeder.

Sample paragraphs

The main tense in this first sample is past. Tense shifts are inappropriate and are indicated in bold.

The gravel crunched and spattered beneath the wheels of the bus as it swung into the station. Outside the window, shadowy figures peered at the bus through the darkness. Somewhere in the crowd, two, maybe three, people were waiting for me: a woman, her son, and possibly her husband. I could not prevent my imagination from churning out a picture of them, the town, and the place I will soon call home. Hesitating a moment, I rise from my seat, these images flashing through my mind.

 (adapted from a narrative)

Inappropriate shifts from past to present, such as those that appear in the above paragraph, are sometimes hard to resist. The writer becomes drawn into the narrative and begins to relive the event as an ongoing experience. The inconsistency should be avoided, however. In the sample, will should be would, and rise should be rose.

The main tense in this second sample is present. Tense shifts—all appropriate—are indicated in bold.

A dragonfly rests on a branch overhanging a small stream this July morning. It is newly emerged from brown nymphal skin. As a nymph, it crept over the rocks of the stream bottom, feeding first on protozoa and mites, then, as it grew larger, on the young of other aquatic insects. Now an adult, it will feed on flying insects and eventually will mate. The mature dragonfly is completely transformed from the drab creature that once blended with underwater sticks and leaves. Its head, thorax, and abdomen glitter; its wings are iridescent in the sunlight.

 (adapted from an article in the magazine Wilderness)

This writer uses the present tense to describe the appearance of a dragonfly on a particular July morning. However, both past and future tenses are called for when she refers to its previous actions and to its predictable activity in the future.

Verbs with Helpers

1. Recent Past (Present Perfect)

A conjugation of Have + [VERB+ed] describes an action that began in the past and continues into the present or that occurred in the recent past.

Examples:

• The child has finished the candy.

• I have gone to college for one year.

• He has worked hard all day.

2. Distant Past (Past Perfect)

Had + [VERB+ed] describes actions that began and ended in the past.

Examples:

• Mike had promised to repair Joe's bike.

• I had eaten dinner before he came.

3. Present Continuous Action (Present Progressive)

Is + [VERB+ing] shows action that is in progress now or is going to happen in the future.

Examples:

• I am taking Spanish this semester.

• He is getting ready for the party this evening.

• Next week they are going to Florida.

4. Past Continuous Action (Past Progressive)

Was + [VERB+ing] shows action that was in progress at a certain time in the past.

Examples:

• Yesterday I was working in the garden.

• He was smoking a pack a day before he quit.

• The dogs were barking all night.

5. Other helping verbs (Modals)

[HELPER] + [VERB], such as CAN, WILL, SHALL, MAY, COULD, WOULD, SHOULD, MIGHT, MUST keep the same form. They do not change to agree with the subject.

Examples:

I |

you |

he | can do that assignment easily.

we |

There are also modal phrases (some of which don't change form), such as:

• COULD HAVE + Verb

• WOULD HAVE + Verb

• MUST HAVE + Verb

(Not could "of" or would "of")

Examples:

• I could have won the prize if I had entered the contest.

• He must have bought the ticket already.

OR

• USED TO + Verb

• HAVE TO + Verb

• HAVE GOT TO + Verb

• BE ABLE TO + Verb

• OUGHT TO + Verb

• BE SUPPOSED TO + Verb

Examples:

• I used to think that all dogs have fleas.

• I am supposed to come back next week.

精彩推文回顾

• 语言教学 | 普渡大学写作教学系列General Writing 01-The Writing Process and List

• 语言教学 | 普渡大学写作教学系列General Writing 10-Thesis Statement