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The third conditional: 'could have', would have', and 'should have'
finding a job

Recently we looked at three uses of the conditional. There is also a fourth type of condition, which is often referred to as the third conditional.

Hani Al-Shoulah from Saudi Arabia asks:

Please check the following sentence for me: ‘I had never should leave the job.’ What I mean is that the action of leaving the job has been made. After that, I recognised that what I did was wrong. Therefore, is the tense of the above-mentioned sentence correct? If not, please advise me.


Roger replies:more questions
It’s not quite right syntactically, Hani. To express this idea, you need should have + past participle, so it should read:
  • 'I should never have left my job.'
For the if clause, you need the past perfect. The main clause would then read:
  • 'I should never have left my job. If I had stayed with BP, I would have won promotion and I would be a rich man now!'
Note that if we wish to give emphasis to the condition and make it sound more dramatic and formal, we can omit if in the subordinate clause and invert subject and verb:
  • 'Had I stayed with my previous job, I would have won promotion and we wouldn’t be in this unfortunate position now.'
Consider the following:
  • 'I shouldn’t have gone to Jane’s place for the weekend. If I’d stayed in London, we could have worked on that report and it would be finished by now.'

  • 'I should never have agreed to take that parcel on the plane for him. But I had no idea what was in it. If only I had said ‘no’, I wouldn’t be in prison now.'

In the examples above, note that if only is used to express a strong wish or regret and that could have suggests a probable or possible outcome (cf. might have.)

Here are some further examples of the latter:

  • 'We might have won the match, if Beckham had been playing from the beginning.'

  • 'I might have gone to school in America, if my parents hadn’t moved to Singapore.'

  • 'We could have finished that cup of coffee, if you hadn’t insisted on us being here five minutes early.'

  • 'If cholera had been diagnosed earlier, his life could have been saved.'
Note the further variations in the above sentences. In the final example, it is convenient to use the passive voice instead of active voice: 'If they had diagnosed cholera earlier, he might not have died.' And in the David Beckham example, there is a slight preference for past perfect progressive rather than past perfect to emphasise the continuity aspect.

Finally, do you remember those first three uses of the conditional?

Conditions that are generally true, where we use the present simple in both subordinate and main clause I stay inside if the temperature falls below –25°C. I just don’t go out.
Situations where we are predicting a future event if the condition is met and where we use future reference in the main clause and the present simple in the subordinate clause You’ll feel much better tomorrow if you stay at home today
Conditions where something unreal is being discussed and
where we use would in the main clause and past simple in the
subordinate clause
Would you accept a diamond ring if he offered it to you? I wouldn’t!


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