51.2.2 Si+ pluperfect subjunctive + conditional perfect/pluperfect subjunctive
A condition which was not fulfilled is expressed with si, ‘if’, plus a pluperfect
subjunctive, e.g. Si me hubieran/hubiesen escuchado... , ‘if they had listened to
me.. .’, followed by a conditional perfect or a pluperfect subjunctive in the main
clause, e.g. no habría sucedido or no hubiera sucedido, ‘it would not have happened’.
Note however that whereas in the si-clause one can use either the -ra or -se form of the
pluperfect subjunctive (e.g. hubiera or hubiese), the pluperfect subjunctive in the
main clause normally takes the -ra form (e.g. hubiera). 16.1.1.3 (p. 61); 16.1.1.7 (p. 62)
Si me lo hubieras/hubieses pedido te habría/hubiera ayudado.
If you had asked me I would have helped you.
Si lo hubiera/hubiese sabido no habría/hubiera venido.
If I had known I wouldn’t have come.18.2.4 (p. 89); 18.2.3 (p. 88)
51.3 Other conditional expressions
51.3.1 De+ infinitive instead of si-clause
The si-clause can be replaced by de+ infinitive, especially in unfulfilled conditions.
Generally, however, this alternative is possible when the subject of the si-clause and
that of the subordinate clause are the same. Its use is more common in the spoken
language.
Si hubiera/hubiese tenido tiempo habría/hubiera asistido a la
reunión.
De haber tenido tiempo habría/hubiera asistido a la reunión.
If I had had time I would have attended the meeting.
Si hubiéramos/hubiésemos viajado en tren no habríamos/
hubiéramos llegado a tiempo a la boda.
De haber viajado en tren no habríamos/hubiéramos llegado a tiempo
a la boda.
If we had travelled by train we wouldn’t have arrived on time for the
wedding.
De is often used with ser in sentences like the following, where the subject of the
si-clause is different from that of the main clause.De ser así tendremos que volver. (Si es así.. .)
If it is like that we’ll have to come back.
De ser como tú dices no queda otra alternativa. (Si es como tú
dices.. .)
If it is as you say there is no other alternative.EXPRESSING CONDITIONS 51.3