Conditional sentences are categorized based on the likelihood and time frame of the conditions they describe. The third conditional deals with hypothetical situations in the past and their imagined outcomes, using the structure "
We can also use: going to future/ can/could/ might instead of will
If X happens, Y will happen. These sentences describe what the speaker thinks will possibly happen as a consequence of a real situation. Ex.:If we do not deal with the global warming problem, temperatures will rise
REAL CONDITIONS
ZERO CONDITIONAL
IF/WHEN PRESENT SIMPLE + PRESENT SIMPLE
If X happens, Y happens. These sentences describe what always happens in certain circumstances, e.g. scientific facts: Ex.: When/ if you press the switch, the light comes on
ALWAYS TRUE
Topic principal
THIRD CONDITIONAL
If + PAST PERFECT, + WOULD HAVE + VERB (PARTICIPLE)
We also use might have or could have in place of would have
If X happened, Y would have pappened. These sentences describe what the speaker thinks would have happened as a consequence of a situation which is in the past, so it´s impossible to change. Ex.: If I'd seen you, I would have said hello
IMPOSSIBLE or PAST CONDITION
SECOND CONDITIONAL
IF PAST SIMPLE + WOULD +VERB (BASE FORM)
The past simple tense we use in an If- clause does not describe past time, but unreal time. We use also might or could in place of would
If X happened, Y would happen. These sentences describe what the speaker thinks would happen in an imaginary situation. Ex.: If you were in Venus, you would see the sun rise in the west