Should and were to can also be used in the if-clauseA group of related words containing a subject and a verb. of third conditional sentences. To express that the sentence refers to past, however, a perfectThe aspect expressing completion. E.g.: He’s finished university. infinitive is used after them. Note that this usage (like the situation it expresses) is not very common.

SHOULD

Should + perfectThe aspect expressing completion. E.g.: He’s finished university. infinitive can be used to emphasisSpecial importance or attention given to something. E.g.: All I wanna do is have some fun.e unlikelihood in the past. This use is rather formalNot belonging to colloquial or everyday speech; official. E.g.: I demand that Mr Smith call the person on whom the committee has decided. or may even sound archaic to some speakers.

The past perfectThe aspect expressing completion. E.g.: He’s finished university. subjunctive has the same form as the past perfect tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses..

had + past participle

It is used in subordinate clauseA clause that cannot be a sentence in itself. It is joined with a main clause. E.g.: I wouldn’t go there if I were you. ("if I were you") When I arrived he was surfing. ("when I arrived")s and expresses an unrealA tense that expresses a hypothetical situation. E.g.: I wish you were here. past situation:

The past subjunctive has the same form as the simple past, except in the case of the verbA part of speech that expresses an action or a state. E.g.: John seldom plays tennis. be, the past subjunctive form of which is either I/he/she/it was or I/he/she/it were.

When reporting a third conditional, we apply no tenseA grammatical category that is marked by verb inflection. To express when an event or action happens in time or when a state exists, we use tenses. changes.

"If they had been more careful, they wouldn't have been killed in the accident", the policeman muttered.
The policeman remarked that they wouldn't have been killed in the accident if they had been more careful.

subject 1 + would rather/sooner + clause (subject 2 + past perfect)

I’d rather we had never met. (= If only we had never met.)
What would you rather I had written? (= What do you wish I had written?)

would rather/sooner + perfect infinitive

This structureThe way in which the parts of a sentence, clause or expression are arranged. E.g.: make somebody + infinitive in "The teacher made me rewrite the composition." can express preferences in the past.

Would you rather have had pork than veal?
I’d rather not have called the police.

If we delete the word rather, we get the main clauseA clause that could be a sentence in itself. E.g.: I wouldn’t go there if I were you. ("I wouldn't go there") When I arrived he was surfing. ("he was surfing") of a third conditional sentence.

wish/if only + subject + past perfect

In this type of mixed conditional the if-clauseA group of related words containing a subject and a verb. is in the second, while the main clauseA clause that could be a sentence in itself. E.g.: I wouldn’t go there if I were you. ("I wouldn't go there") When I arrived he was surfing. ("he was surfing") is in the third conditional.

If Mr Douglas had a moustache, Ms Zeta Jones would probably not have married him.
If I were smarter, I would have been able to answer.

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