References

First Conditional
http://www.esl-lounge.com/level2/lev2firstconreview.shtml
http://www.youtube.com/watch?v=ow8FIHbwekU by JenniferESL

Second Conditional
http://www.learnenglishfeelgood.com/g-grammar-secondconditional2.html
http://www.youtube.com/watch?v=CdHbkjCviC0 by JenniferESL

Third Conditional
http://www.esl-lounge.com/level4/lev4thirdcondwsheet.shtml
http://www.youtube.com/watch?v=KxjoTZOdyfU by JenniferESL
http://www.youtube.com/watch?v=tGcwG-2owow
http://www.youtube.com/watch?v=aJwTRvgsfUw

Grammar exercise
http://www.esl-lounge.com/student/grammar/2g42-what-do-you-do-if.php

Writing exercise
http://netgrammar.altec.org/Units/Unit_15/a101c15_501000.html