Conditional Sentences

True conditional sentences are subject to certain terms or imply conditions or preconditions or a prescribed set of steps or circumstances or involve possibilities or assumptions or suppositions (hypothetical) before a goal or objective may be achieved.

Zero Conditional: refers only to what is true or factual.

If (when) you say something, I'm not surprised. = whatever you say doesn’t surprise me. = nothing you say surprises me.

1st Conditional: refers to real possibilities and the results

If you say something, it won’t surprise me. = whatever you say won’t surprise me. = nothing you say will surprise me.

2nd Conditional: refers to less real possibilities or events that are not expected or that one has difficulty imagining and the results

If you said something, it wouldn’t surprise me. = whatever you said wouldn’t surprise me. = nothing you said would /could surprise me.

3rd Conditional: refers to events that didn’t happen and the results (if they had happened).

If you had said something, I wouldn’t have been surprised = whatever you could /might have said wouldn’t have surprised me = Nothing you could /might have said would have surprised me.  

Mixed Conditionals

Mixed conditionals combine two different types of conditional patterns. They are usually a combination of a 2nd conditional and a 3rd conditional or a 1st conditional and a 2nd conditional.

 Mixed conditionals always involve some element of truth, allow more flexibility in meaning, and often express what can’t be expressed using standard conditional structures.

Mixed: If + past perfect (3rd conditional), + 2nd conditional (would /could /might etc. in the main clause

Mixed: If you had /have said something, I wouldn’t /couldn’t /might not be surprised.

 The speaker is referring to a past event or a recent past event (in the ‘if clause’) but doesn’t know whether it took place or not i.e. whether the person said something or didn’t say anything. If the person then tells the speaker he did indeed say something, the speaker has already given their reaction. In this example, the mixed conditional shows the present results of a past event.

3rd Conditional: If you had said something, I wouldn’t have been surprised.

In this case, the speaker already knows nothing was said but if at the time something had been said, the speaker at the time would not have been surprised.

A 3rd conditional cannot show present results of a past event because nothing happened i.e. the event didn’t take place.

Mixed: If + 1st conditional (present or present continuous) + 2nd conditional (would /could/ might) in the main clause

 If you say /you’re going to say something, I would /could /might be surprised.

1st Conditional: If you say something, I’ll be surprised.
In both cases predictions are being made but in which case would the speaker be more surprised?

 Mixed: If + 3rd conditional (would've + past participle) + 2nd conditional (past simple) in the main clause.

If he had taken the pharmaceutical drug, he would still be sick

 3rd Conditional: If he had taken the pharaceutical drug, he would have still been sick.

Both the mixed and 3rd conditional convey the same idea; an (imagined) event that did not take place and the current /present result. The person did not take the prescribed pharmaceutical drug and therefore got better without it.