Present and past subjunctive
The terms present subjunctive and past subjunctive can be misunderstood, as they describe forms rather than meanings: the past and present subjunctives are so called because they resemble the past and present indicatives, respectively, but the difference between them is a difference in modality, not a temporal one.
For example, in "I asked that it be done yesterday," be done (a present subjunctive) has no present-tense sense; and likewise, in "If that were true, I would know it," were (a past subjunctive) has no past-tense sense.
[edit] The pluperfect subjunctive
Since the "past subjunctive" is not a true past tense, it uses as its past tense what is structurally its perfect aspect form. This past tense is known as the past perfect subjunctive or pluperfect subjunctive; it is formed using had (the past subjunctive of to have) plus the verb's past participle.
The pluperfect subjunctive is used like the past subjunctive, except that it expresses a past-tense sense. So, for example:
* If I had known (yesterday), I would have done something about it.
* If I had seen you, I definitely would have said hello.
* I would not be here if he had not helped me.
When used in the construction of a counterfactual statement as in the examples above, it is paired with the conditional perfect viz. "If I had [not] X, then I would [not] have Y". The (arguably) canonical example of the counterfactual actually eschews the pluperfect subjunctive: If I Knew You Were Comin' I'd've Baked a Cake.
If a clause is in a past tense, then a clause subordinate to it cannot be in the past subjunctive, though it might be in the pluperfect subjunctive; however, if it is in a present tense, then a clause subordinate to it might be in either of the two, depending on meaning.
The pluperfect subjunctive is often replaced with the past subjunctive in colloquial speech, a substitution that is commonly considered incorrect. (See prescription and description.)
(Note that by contrast, the present perfect subjunctive — that he have done — while logically and theoretically possible, is not much used in modern English.)
[edit] Future subjunctive
A future subjunctive can be constructed using the conjugated form of the verb "to be" plus the infinitive or with the usage of the modal auxiliary verb "should". Note that the "were" clauses result in the present conditional, while the "should" clauses result in the future indicative. For example:
* If I were to die tomorrow, then you would inherit everything.
* If you were to give the money to me, then I would say no more about it.
* If I should go, then will you feed the hens?
* If he should fall, who will carry the flag in his place?
[wiki]
The terms present subjunctive and past subjunctive can be misunderstood, as they describe forms rather than meanings: the past and present subjunctives are so called because they resemble the past and present indicatives, respectively, but the difference between them is a difference in modality, not a temporal one.
For example, in "I asked that it be done yesterday," be done (a present subjunctive) has no present-tense sense; and likewise, in "If that were true, I would know it," were (a past subjunctive) has no past-tense sense.
[edit] The pluperfect subjunctive
Since the "past subjunctive" is not a true past tense, it uses as its past tense what is structurally its perfect aspect form. This past tense is known as the past perfect subjunctive or pluperfect subjunctive; it is formed using had (the past subjunctive of to have) plus the verb's past participle.
The pluperfect subjunctive is used like the past subjunctive, except that it expresses a past-tense sense. So, for example:
* If I had known (yesterday), I would have done something about it.
* If I had seen you, I definitely would have said hello.
* I would not be here if he had not helped me.
When used in the construction of a counterfactual statement as in the examples above, it is paired with the conditional perfect viz. "If I had [not] X, then I would [not] have Y". The (arguably) canonical example of the counterfactual actually eschews the pluperfect subjunctive: If I Knew You Were Comin' I'd've Baked a Cake.
If a clause is in a past tense, then a clause subordinate to it cannot be in the past subjunctive, though it might be in the pluperfect subjunctive; however, if it is in a present tense, then a clause subordinate to it might be in either of the two, depending on meaning.
The pluperfect subjunctive is often replaced with the past subjunctive in colloquial speech, a substitution that is commonly considered incorrect. (See prescription and description.)
(Note that by contrast, the present perfect subjunctive — that he have done — while logically and theoretically possible, is not much used in modern English.)
[edit] Future subjunctive
A future subjunctive can be constructed using the conjugated form of the verb "to be" plus the infinitive or with the usage of the modal auxiliary verb "should". Note that the "were" clauses result in the present conditional, while the "should" clauses result in the future indicative. For example:
* If I were to die tomorrow, then you would inherit everything.
* If you were to give the money to me, then I would say no more about it.
* If I should go, then will you feed the hens?
* If he should fall, who will carry the flag in his place?
[wiki]