2013/01/26

Type 0
   oDescribing real and possible events.
   oDescribing now and always.

   oFacts, scientific facts, general truths



          Form
   oBoth parts of the sentence are in the simple present tense.

   oIf you freeze water, it becomes a solid.
   oPlants die if they don't get enough water.
   oIf public transport is efficient, people stop using their cars.
   oIf you mix red and blue, you get purple. 
                                                           Type 1
oDescribing possible and probable events.
oDescribing now and future.

oFacts used to make statements about the real world and about particular situations. 
Form
oThe ‘if’ sentence is in the simple present tense, and main clause is in the simple future tense.

oIf you don't leave, I'll call the police.
oIf you don't drop the gun, I'll shoot!
oIf you drop that glass, it will break.
oIf I have time, I'll finish that letter.
oWhat will you do if you miss the plane?

Reasons to use conditionals
oThey are used to express that the action in the main clause (without if) can only take place if a certain condition (in the clause with if) is fulfilled.

oIf you freeze water, it becomes a solid.
oIf you don't leave, I'll call the police.

oProving a point
oConvincing someone
oGiving reason
oShowing a relationship between 2 things

SUMMARY

Type 0:  Describing facts
If + simple present tense, + simple present tense.
Type 1:  Describing possible situations
If + simple present tense, + simple future tense
(should/may/can).
Type 2:  Describing unreal/ imaginary situation in   the present / future
If + simple past tense, +  would(should/might/could) + basic form.

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