VII. Adverbial when -clauses using an absolute tense form 679 In theory, the sentence When I’ve seen Bill he’s always been in prison is equally ambiguous, but in practice it will normally be interpreted in terms of simulta- neity. (For the anteriority reading we would say When I’ve seen Bill he’s always just been in prison.) 680 13. Adverbial when -clauses and the use of tenses VIII. When -clause and head clause referring to different times A clause obviously uses an absolute tense form if it locates its situation time in a different time-sphere from the head clause. 13.18 Head clause referring to the past and when-clause referring to the present This kind of ‘mismatch’ of time-spheres is not normally possible in adverbial when-clauses. However, we might note in passing that such a mismatch can occur in when-clauses functioning as restrictive relative clauses forming part of a temporal adverbial. It may be due to the fact that the relative when-clause has generic meaning (i. e. expresses a universal truth) or to the fact that the when-clause refers to a habitual situation which holds not only at the time of the head clause situation but also at t 0 : During the latter part of May and early in June the weather was unusually cold and wet, and growth was checked at a time when the quality teas of the year are made. (LOB) I had reached the age when sexual questions pester the imagination (LOB) There are also examples in which the relative when-clause refers to a single (nonhabitual and nongeneric) situation which is located at t 0 even though the head clause is in the past tense. The combination of a when-clause in the present tense with a head clause in the past tense is rendered possible by the fact that the when-clause situation covers a time span which contains not only the head clause situation but also t 0 : [Word of Dag Hammarskjöld’s death ( ) has sent a shockwave around the globe. ( ) He was the symbol of world peace, and] his tragic end came at a moment when peace hangs precariously. (BR) The following is an example in which the present tense is similarly used in a when-clause that is an adverbial (rather than relative) when-clause: [Do we want to go through this? Or can we ask you why] you changed your forecast just when it’s about to be right? (WSJ) VIII. When -clause and head clause referring to different times 681 13.19 Head clause referring to a past domain and when-clause referring to the post-present In the following examples, the adverbial when-clause refers to the post-present, although the head clause uses a past time-sphere tense (incorporating the situa- tion time of the head clause into a past domain): [He added that ( )] child-care provisions would be part of the reconciliation bill when it is sent to the president. (WSJ) [Last month Sir William Morgan ( ) said that] when existing orders are completed the company would stop making rolling stock for railways (LOB) In these examples, the when-clause situation is W-simultaneous with a head clause situation that is itself represented as T-posterior to a past orientation time. In this type of sentence we would expect the when-clause to use a relative past tense form, and that is indeed the default choice, but the form that is actually used in these examples is a present tense form, i. e. a form from the Pseudo-t 0 -System which is used to represent its situation time as T-simulta- neous with a post-present binding orientation time (and in doing so establishes a post-present way in an ‘indirect’ way Ϫ see 9.22.1). This is made possible by the fact that the situation time of the when-clause is W-posterior not only to the situation time of the head clause but also to t 0 . Although examples like these resemble those in 13.18, they differ from those in that, unlike the relative when-clauses in 13.18, the adverbial when-clauses in the above examples cannot use an absolute tense form. 13.20 Head clause referring to the pre-present and when-clause referring to the present When the head clause does not refer to a habitual-repetitive situation and uses a so-called ‘indefinite’ present perfect (see 5.4), it cannot support a when-clause: I have seen him. *I have seen him when he came in just now. It is typical of an indefinite perfect interpretation that the exact location of the situation time in the pre-present must remain indefinite. Hence the impossibil- ity of adding a when-clause indicating a specific time. However, it was noted in section 13.17 that a when-clause can be added if the head clause receives a habitual-repetitive interpretation. In that case the when-clause can use either the present perfect or the past tense: John has batted well when he has played. (HORN) I have often been in Japan when the cherry trees were in bloom. 682 13. Adverbial when -clauses and the use of tenses However, apart from examples like these, we can also find examples in which the when-clause uses the present tense: I’ve only ever met Mrs Cunliffe when she comes round collecting signatures for protest petitions. (MAR) I tried to explain what has happened, unfailingly, whenever a significant body of Negroes move North. (BR) In examples like these, the use of an absolute present tense in a when-clause depending on a head clause in the present perfect is made possible by the fact that the when-clause refers to a habitual-repetitive situation, instances of which are to be found not only in the pre-present but also in the present. What happens is that the speaker changes track between head clause and when- clause. He first wants to talk about his (lack of) experience, which means referring to the time-up-to-now and then he wants to talk about the presentness of the habit which produces that experience. IX. Summary 683 IX. Summary In this chapter on adverbial when-clauses we have presented an analysis of the temporal structure expressed by when and examined the possibilities of tense choice in adverbial when-clauses and in the head clauses supporting them. The following are the main conclusions we have arrived at: (a) The temporal structure expressed by when is that of a common Adv-time containing both an orientation time from the tense structure of the head clause (ϭ the contained orientation time of the head clause) and an orien- tation time from the tense structure of the when-clause (ϭ the contained orientation time of the when -clause). This temporal structure, which is the semantics of when, can therefore be paraphrased as ‘at a/the time at which’. (b) The when-clause can specify either the situation time of the head clause or an orientation time which binds the situation time of the head clause in terms of T-anteriority or T-posteriority. In other words, the when-clause can be used either as a situation-time adverbial or as an orientation-time adverbial. (c) In both cases the when-clause uses a relative tense, which represents the situation time of the when-clause as T-anterior, T-simultaneous or T-poste- rior to the contained orientation time of the when-clause. (d) It follows from (b)Ϫ(c) that there are nine unmarked configurations of temporal relations, realizing nine different temporal structures involving the common Adv-time expressed by when. These nine configurations, which have in common that the situation time of the when-clause is bound by the contained orientation time of the when-clause, can be considered as forming the set of unmarked options as far as tense choice is concerned. As the examples have shown, all nine of them are compatible with refer- ence to the past as well as with reference to the post-present. 12 (e) Apart from the unmarked options, there are some marked uses of tenses in adverbial when-clauses. Under certain conditions the when-clause can use the past perfect (but not the conditional tense or the conditional per- fect!) to effect indirect binding, i. e. to T-relate the situation time of the when-clause to an orientation time which is not the contained orientation time of the when-clause (and which is not t 0 either). There are also cases in which the when-clause uses the conditional tense or conditional perfect in order to express irrealis, i. e. in order to represent the actualization of 12. Like time-specifying adverbials such as at five o’clock, Adv-time-when-clauses are nor- mally incompatible with reference to the present, except in special cases (summaries, habitual-repetitive sentences, etc.). 684 13. Adverbial when -clauses and the use of tenses the when-clause situation as counterfactual or tentative. Finally, it is pos- sible for the when-clause to shift the domain to the post-present, in which case a form from the Pseudo-t 0 -System has to be used. Since all these cases represent a marked tense choice, they are relatively uncommon and subject to severe restrictions. 14. Adverbial before-clauses and after-clauses I. Adverbial before -clauses 657 A. Introduction 657 14.1 Terminology 657 14.2 The temporal structure of before 657 14.3 Temporal structures involving a head clause and a before-clause 688 14.4 The nature of past tense forms in before-clauses 692 B. The tense system if the before-clause is a situation-time adverbial 698 14.5 Absolute tense forms in both before-clause and head clause 699 14.6 Absolute tense in the head clause and relative tense in the before-clause 707 14.7 Relative tense in head clause and relative tense in before-clause 717 14.8 Relative tense in head clause and absolute tense in before-clause 721 14.9 Summary of section B 725 C. The tense system if the before-clause is an orientation-time adverbial 727 14.10 Using a before-clause as orientation-time adverbial 727 D. Factual, not-yet-factual and counterfactual before-clauses 729 14.11 Factual interpretations of before-clauses 729 14.12 Counterfactual before-clauses 735 14.13 Not-yet-factual before-clauses 736 E. A comparison between before and until 738 14.14 The semantics of the conjunction until 738 14.15 The tenses used in head clause and until-clause 739 14.16 The semantics of not…until 740 II. Adverbial after -clauses 742 14.17 The temporal structure of after 742 14.18 Temporal structures involving a head clause and an after-clause 745 14.19 The tense system if the after-clause functions as situation-time adverbial 747 14.20 The tense system if the after-clause functions as orientation-time adverbial 750 III. Summary 754 14.21 Summary of the discussion of before-clauses 754 14.22 Summary of the discussion of after-clauses 756 . structure of the head clause (ϭ the contained orientation time of the head clause) and an orien- tation time from the tense structure of the when-clause (ϭ the contained orientation time of the when -clause) temporal structure, which is the semantics of when, can therefore be paraphrased as ‘at a /the time at which’. (b) The when-clause can specify either the situation time of the head clause or an orientation. only at the time of the head clause situation but also at t 0 : During the latter part of May and early in June the weather was unusually cold and wet, and growth was checked at a time when the quality