Using “would”​, “should”​ and “could”​ – the basics

The grammar construction in [2] to [4] below is identical with the grammar construction in [5] to [7]; often there is little difference of the concept and/or meaning between [2] to [4] and [5] to [7].

In [2] to [10] below there are 2 clauses in each sentence. The clauses may be reversed. The “if” clause can be missed out. My examples all contain “I”, but other “persons” (“you” etc.) can be freely used. In [2] to [7], the three dots should be replaced by words starting with the basic form of a verb.

  1. Could = was able to, were able to
  2. Unlikely future, impossible future – If I won £1,000,000, I would… (prediction – likely result of winning £1000,000)
  3. Unlikely future, impossible future – If I won £1,000,000, I could… (=would be able to…)
  4. Unlikely future, impossible future – If I won £1,000,000, I should… (=would be advised to…, it would be advisable for me to…)
  5. Untrue present – If I owned £1,000,000, I would… (likely resulting untrue present – the result of owning £1,000,000)
  6. Untrue present – If I owned £1,000,000, I could… (=would be able to…)
  7. Untrue present – If I owned £1,000,000, I should… (=would be advised to…, it would be advisable for me to…)
  8. Untrue past – If I had won £1,000,000, I would have … {gone/done etc.} (likely resulting past – of having won £1,000,000)
  9. Untrue past – If I had won £1,000,000, I could have…{gone/done etc.} (=would have been able to …{go/do etc.})
  10. Untrue past – If I had won £1,000,000, I should have… {gone/done etc.} (=would have be advised to… {go/do etc.}, it would have been be advisable for me to …{go/do etc.})
  11. There are important uses of these words based on [2] to [7] above; in these, the “if” clause is often or usually missed out. Some of them are below:-
  • “Would” to politely express desire – a version of [2] or [5]: “I would like….”
  • “Would” – a gentle way of asking what someone wants for the future – perhaps because you want to appear tentative about the future – a version of [2]: “Would you like…?”
  • “I should……” – polite way to give advice – a version of [7], with an implied “if I were you” (=“if I exchanged positions with you”)
  • “You could” – gentle way of saying “you can” – a version of [3] or [6] above with an implied “if you wanted”