Sequence of tenses

The sequence of tenses (known in Latin as consecutio temporum, and also known as agreement of tenses, succession of tenses and tense harmony) is a set of grammatical rules of a particular language, governing the agreement between the tenses of verbs in related clauses or sentences.
A typical context in which rules of sequence of tenses apply is that of indirect speech. If, at some past time, someone spoke a sentence in a particular tense (say the present tense), and that act of speaking is now being reported, the tense used in the clause that corresponds to the words spoken may or may not be the same as the tense that was used by the original speaker. In some languages the tense tends to be "shifted back", so that what was originally spoken in the present tense is reported using the past tense (since what was in the present at the time of the original sentence is in the past relative to the time of reporting). English is one of the languages in which this often occurs. For example, if someone said "I need a drink", this may be reported in the form "She said she needed a drink", with the tense of the verb "need" changed from present to past.
The "shifting back" of tense as described in the previous paragraph may be called backshifting or an attracted sequence of tenses. In languages and contexts where such a shift does not occur, there may be said by contrast to be a natural sequence.
English.
In English, an "attracted sequence" of tenses (backshifting) is often used in indirect speech and similar contexts. The attracted sequence can be summarized as follows: If the main verb of a sentence is in the past tense, then other verbs must also express a past viewpoint, except when a general truth is being expressed.
For example, if Batman spoke the following words:
the speech act may be reported using the following words:
with the present tense "need" replaced by the past tense "needed", since the main verb of saying ("said") is in the past tense. Further examples can be found at .
In some cases, though, a "natural sequence" of tenses is more appropriate. Here the tense of a verb in a subordinate clause is not determined by the tense of the verb in the superordinate clause, but is determined simply according to the sense of the clause taken apart from the rest of the sentence. The rule for writers following the natural sequence of tenses can be expressed as follows: imagine yourself at the point in time denoted by the main verb, and use the tense for the subordinate verb that you would have used "at that time". Thus the tense used in the indirect speech remains the same as it was in the words as originally spoken. This is normal when the main verb is in the present or future tense (as opposed to past tense or conditional mood). For example:
However it is also possible to use the natural sequence even if the main verb is past or conditional:
This option is more likely to be used when the circumstance being expressed remains equally true now as it did when the speech act took place, and especially if the person reporting the words agrees that they are true or valid.
Debate amongst grammarians over the appropriateness of the two types of sequence of tenses goes back as far as the 18th century. Use of the attracted sequence sometimes leads to additional problems when the grammatical construction of indirect speech includes an incorporated quotation – that is, when an attempt is made (though using indirect rather than direct speech) to report the words actually spoken. For example, if a minister spoke the words "Such a policy is not without its drawbacks", then a writer may attempt to report this as follows:
using quotation marks to denote that that portion of the sentence represents the minister's actual words. This, however, requires use of the natural sequence of tenses, which might not be felt appropriate in the given situation. There are various possible solutions to this problem:
Similar problems arise from the other changes that typically occur in indirect speech, such as changes of pronoun (depending on speaker), etc.
For more details, see the article on indirect speech, and also the article on uses of English verb forms, particularly the sections on indirect speech and dependent clauses.
Russian.
Indirect speech in Russian and other Slavic languages generally uses the natural sequence of tenses (there is no backshifting). For examples, see .
Latin.
In Latin, the sequence of tenses rule affects dependent verbs in the subjunctive mood, mainly in indirect questions, indirect commands, and purpose clauses. If the main verb is in one of the non-past tenses, the subordinate verb is usually in the present or perfect subjunctive (primary sequence); if the main verb is in one of the past tenses, the subordinate verb is usually in the imperfect or pluperfect subjunctive (historic sequence). For example, when the subordinate verb refers to a time contemporaneous or later than the time of the main verb, the present or imperfect subjunctive is used:
When the subordinate verb refers to a time earlier than that of the main verb, the perfect or pluperfect subjunctive is used:
If the main verb is a historic present (i.e. a present tense with a past meaning), either primary or historic sequence may be used, or in a long sentence even a mixture of the two:
If the main verb is a perfect tense, it is usually followed by the historic sequence, but if the meaning is equivalent to an English present perfect (i.e. "have done"), it may be followed by primary sequence:
There are frequent exceptions to the sequence of tenses rule (see Latin tenses#Sequence of tenses rule). For example, verbs in conditional clauses do not usually follow the rule:
Consecutive clauses also do not always follow the rule:
When the sentence is an indirect statement (which uses the accusative and infinitive construction in Latin), the main verb of the reported sentence is an infinitive which remains unchanged, no matter what the tense of the main verb. The present infinitive is used for a situation contemporaneous with the main verb:
The perfect infinitive is used for an event or situation earlier than the time of the main verb:
However, subordinate clauses in an indirect statement use the subjunctive mood, which is subject to the sequence of tenses rule:
Greek.
In Classical Greek, the tenses in subordinate clauses must correspond to those in the superordinate clauses governing them.
A principal tense (present tense, future tense, or perfect tense) in the superordinate clause is followed by a principal tense in the indicative mood or subjunctive mood. Such a principal tense is followed by:
A historical tense (imperfect, pluperfect, or aorist) in the superordinate clause is followed by a historical tense in the indicative mood or optative mood. Such a historic tense is followed by:
Italian.
The set of rules comprising the sequence of tenses (and modes of the main and subordinate clauses) in the Italian language corresponds in general to the "consecutio temporum" of the Latin grammar.
To determine the form of the verb in the subordinate clause it is necessary to know:
The various combinations are summarized in four tables (see below).
Sequence of tenses of the indicative.
The verb of the main clause is a past tense.
If the verb of the main clause is in the past (simple past, imperfect, or past perfect), the verbal forms of the subordinate clause refer to the moment indicated in the main clause and adapt accordingly. The present in the subordinate clase will transform to imperfect, the past will become past perfect, etc.:
Sequence of tenses of the subjunctive.
Despite of the use of the subjunctive, the verbal tenses follow rules similar to the ones of the Indicative mood. The Present Indicative of the subordinate clause will be substituted with the subjunctive present; similarly, the present perfect will be substituted with its correspondent form, that of the past subjunctive and the Past perfect tense with the subjunctive past perfect.
The verb of the main clause is a past tense.
If the verb of the main clause is in the past tense, the verbal forms of the subordinate will be adapted to that of the main clause: