语言教学 | 普渡大学写作教学系列General Writing 38-Active and Passive Voice

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1、Using Active Versus Passive Voice

In a sentence using active voice, the subject of the sentence performs the action expressed in the verb.

The arrow points from the subject performing the action (the dog) to the individual being acted upon (the boy). This is an example of a sentence using the active voice.

Sample active voice sentence with the subject performing the action described by the verb.

The active voice sentence subject (watching a framed, mobile world) performs the action of reminding the speaker of something.

Each example above includes a sentence subject performing the action expressed by the verb.

View examples of active verb tenses.

2、Active Versus Passive Voice

Active voice is used for most non-scientific writing. Using active voice for the majority of your sentences makes your meaning clear for readers, and keeps the sentences from becoming too complicated or wordy. Even in scientific writing, too much use of passive voice can cloud the meaning of your sentences.

Sentences in active voice are also more concise than those in passive voice because fewer words are required to express action in active voice than in passive.

3、More about Passive Voice

In a sentence using passive voice, the subject is acted upon; he or she receives the action expressed by the verb. The agent performing the action may appear in a "by the..." phrase or may be omitted.

Reasons to Generally Avoid Passive Voice

Sometimes the use of passive voice can create awkward sentences, as in the last example above. Also, overuse of passive voice throughout an essay can cause your prose to seem flat and uninteresting. In scientific writing, however, passive voice is more readily accepted since using it allows one to write without using personal pronouns or the names of particular researchers as the subjects of sentences (see the third example above). This practice helps to create the appearance of an objective, fact-based discourse because writers can present research and conclusions without attributing them to particular agents. Instead, the writing appears to convey information that is not limited or biased by individual perspectives or personal interests.

Recognizing Passive Voice

You can recognize passive-voice expressions because the verb phrase will always include a form of be, such as am, is, was, were, are, or been. The presence of a be-verb, however, does not necessarily mean that the sentence is in passive voice. Another way to recognize passive-voice sentences is that they may include a "by the..." phrase after the verb; the agent performing the action, if named, is the object of the preposition in this phrase.

Helpful Hint

You can recognize passive voice because the verb phrase will include a form of be (was, am, are, been, is). Don't assume that just because there is a form of 'be' that the sentence is passive, however. Sometimes a prepositional phrase like "by the" in the sentences above indicates that the action is performed on the subject, and that the sentence is passive.

4、Choosing Passive Voice

Choosing Passive Voice

While active voice helps to create clear and direct sentences, sometimes writers find using an indirect expression is rhetorically effective in a given situation, so they choose passive voice.

Also, writers in the sciences conventionally use passive voice more often than writers in other discourses. Passive voice makes sense when the agent performing the action is obvious, unimportant, or unknown or when a writer wishes to postpone mentioning the agent until the last part of the sentence or to avoid mentioning the agent at all. The passive voice is effective in such circumstances because it highlights the action and what is acted upon rather than the agent performing the action.

Active	Passive
The dispatcher is notifying police that three prisoners have escaped.	Police are being notified that three prisoners have escaped.
Surgeons successfully performed a new experimental liver-transplant operation yesterday.	A new experimental liver-transplant operation was performed successfully yesterday.
"Authorities make rules to be broken," he said defiantly.	"Rules are made to be broken," he said defiantly.

In each of these examples, the passive voice makes sense because the agent is relatively unimportant compared to the action itself and what is acted upon.

5、Changing Passive to Active Voice

If you want to change a passive-voice sentence to active voice, find the agent in a "by the..." phrase, or consider carefully who or what is performing the action expressed in the verb. Make that agent the subject of the sentence, and change the verb accordingly. Sometimes you will need to infer the agent from the surrounding sentences which provide context.

If you want to change an active-voice sentence to passive voice, consider carefully who or what is performing the action expressed in the verb, and then make that agent the object of a by the...phrase. Make what is acted upon the subject of the sentence, and change the verb to a form of be + past participle. Including an explicit by the... phrase is optional.

6、Further Suggestions for Using Passive and Active Voices

1. Avoid starting a sentence in active voice and then shifting to passive.

Unnecessary shift in voice	Revised
Many customers in the restaurant found the coffee too bitter to drink, but it was still ordered frequently.	Many customers in the restaurant found the coffee too bitter to drink, but they still ordered it frequently.
He tried to act cool when he slipped in the puddle, but he was still laughed at by the other students.	He tried to act cool when he slipped in the puddle, but the other students still laughed at him.

2. Avoid dangling modifiers caused by the use of passive voice. A dangling modifier is a word or phrase that modifies a word not clearly stated in the sentence.

Dangling modifier with passive voice	Revised
To save time, the paper was written on a computer. (Who was saving time? The paper?)	To save time, Kristin wrote the paper on a computer.
Seeking to lay off workers without taking the blame, consultants were hired to break the bad news. Who was seeking to lay off workers? The consultants?)	Seeking to lay off workers without taking the blame, the CEO hired consultants to break the bad news.

3. Don't trust the grammar-checking programs in word-processing software. Many grammar checkers flag all passive constructions, but you may want to keep some that are flagged. Trust your judgment, or ask another human being for their opinion about which sentence sounds best.

The Paramedic Method is an effective process for helping eliminate passive voice.

7、Verbs: Voice and Mood

Active and Passive Voice

Verbs in the active voice show the subject acting. Verbs in the passive voice show something else acting on the subject. Most writers consider the active voice more forceful and tend to stay away from passives unless they really need them.

ACTIVE: Tim killed the chicken hawk.

PASSIVE: The chicken hawk was killed by Tim.

Check out our handout on active and passive verbs.

Indicative, Imperative, and Subjunctive Mood

Most verbs we use are in the indicative mood, which indicates a fact or opinion:

Examples:

• He was here.

• I am hungry.

• She will bring her books.

Some verbs are in the imperative mood, which expresses commands or requests. Though it is not stated, the understood subject of imperative sentences is you.

Examples:

• Be here at seven o'clock. (Understood: You be here at seven o'clock.)

• Cook me an omelette. (Understood: You cook me an omelette.)

• Bring your books with you. (Understood: You bring your books with you.)

When verbs show something contrary to fact, they are in the subjunctive mood.

When you express a wish or something that is not actually true, use the past tense or past perfect tense; when using the verb 'to be' in the subjunctive, always use were rather than was:

Examples:

• If he were here... (Implied: ...but he's not.)

• I wish I had something to eat. (Implied: ...but I don't.)

• It would be better if you had brought your books with you. (Implied: ...but you haven't brought them.)

Review

INDICATIVE: I need some help.

IMPERATIVE: Help me!

SUBJUNCTIVE: If I were smart, I'd call for help.

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