Perfect (grammar) - English

English

The perfect is formed in English by conjugating the auxiliary verb "to have" and then appending the verb's past participle form. Verbs in the perfect can be in the active or passive voice. Active verbs combine "to have" and the past participle form of the main verb ("have done", "They have done so much work"). Passive verbs in the perfect require two past participle verb forms: "been" (the past participle of "to be") and the past participle of the main verb ("has been seen", "He has been seen by the doctor").

The conjugation of the verb "to have" determines the tense of the overall construction: 1) "have" and "has" in the present perfect, 2) "had" in the past perfect, and 3) "will have" and "shall have" in the future perfect.

• Present perfect: "The girl has eaten the cookie."
• Past perfect: "The girl had eaten the cookie before she ate her lunch."
• Future perfect: "The girl will have eaten the cookie by this afternoon."

The perfect can be combined with the progressive aspect, a type of imperfective aspect. In the progressive aspect, the verb "to be" is in the past participle form ("been"), while the main verb is in the present participle form ("has been teaching", "She has been teaching for ten years"). For passive verbs, the main verb is in the past participle form, giving "I have been taught by Socrates" in the passive present perfect simple form but two forms of "to be" are used for the continuous: "has been being taught", "The student has been being taught Latin", rendering the perfect continuous or progressive in the passive voice largely meaningless in English. The auxiliary form of “to have” always precedes the form of "to be" in perfect tenses when using the continuous aspect.

The perfect, the progressive, and the perfect progressive are three of the aspect-like forms used in English. The perfective, imperfective, completive, inceptive, punctual, iterative, and habitual are sometimes considered aspects in English as well.

The tense of the verb "to have" dictates the time of the consequences but not of the action. For example, in the sentence "I have written a novel.", the novel is clearly finished at present: the present tense of the verb "to have" indicates that the consequences -- the state of being an author with a completed novel—are in the present tense, even though the authorship is in the past tense. It may mean, “I am (now) finished with the novel” or it may answer the question “Have you ever written a novel?” “I have written a novel” may have a different meaning from “I wrote a novel”; the novel might have been written in the recent past. For this reason, it is not possible to write, “I have written a novel yesterday.” The sentence “She has come” is likely to mean, “She is here now”, but “She came” does not.

The use of the present perfect rather than the simple past tense can suggest other consequences. The sentence “I have written novels for five years” implies that the person is still writing novels whereas the sentence “I wrote novels for five years” implies that the person has stopped writing novels. The sentence “Have you been to the fair?” suggests that the fair is still going on, while the sentence “Did you go to the fair?” suggests that the fair is over.

The present tense form in the progressive shows that the action began some time ago but is continuing: "I have been working on a new novel for two years." By contrast, the past progressive tense ("I was writing a novel") may connote that an action was interrupted ("I was writing a novel until the telephone rang"); this connotation can also carry over into the pluperfect progressive tense ("I had been writing a novel when she walked in the room to talk to me").

The past perfect (or the pluperfect) has sometimes been called the past-in-the-past. It can be used to refer to one past event that occurred before another past event. For example, “The girl had eaten the cookie before she ate her lunch.” Both the girl’s eating the cookie and the girl’s eating lunch were events in the past, but the former happened before the latter.

Outside the indicative mood, the perfect has only a limited proper existence. Because the English modal verbs are largely defective, and because the English subjunctive mood by itself does not form a true preterite, the verb "to have" is often used to construct past tenses. “To have” forms the contrary-to-fact past conditional. For example, “She can do it if she tries” and “She could do it if she tried” are both conditionals in the present tense; “She could have done it if she had tried” is the past conditional. When forming contrary-to-fact conditionals, English uses verb forms that are one step back in time. For example, the present conditional uses the past tense verbs: “If she had the book, she would read it right now.” The pluperfect (referred to as the past-in-the-past) is one step back in time after the simple past tense and is used for the past conditional: “If she had had the book, she would have read it immediately.” These verbs might not be considered to be truly in the perfect.

“To have” is used for the past tense of epistemic modals. For example, “He cannot be a genius” and “He could not be a genius” are both in the present tense. “He could not have been a genius” is in the past tense. This use of epistemic modals might not be considered to be truly in the perfect. The auxiliary verb “must” does not have a past tense form in modern English, and “to have” can be used for its epistemic meaning (for inferences): “He must have been at least seventy years old.” It is interesting to note that “must have” cannot be used for obligation or prohibition. A sentence such as “He might have worked here five years so far” can be rewritten as “Perhaps he has worked here for five years so far” and is considered a true perfect form by some linguists but not others.