Conditional Tenses

Quick review on zero, first, second and third conditionals.

Zero conditionals are for facts.
 If + present simple + present simple
If you heat water to 100 degrees Celsius, it boils.

First conditionals are for real or possible situations in the future.
If + present simple then will + verb stem
If you study, you will pass the test,

Second conditionals are for hypothetical situations in the present or future.
If + past simple (were instead of was for impossible situations), then would + verb stem
If I had a million dollars, I would buy an apartment in Paris.

Third Conditionals are for an imagined change in the past. 
If + past perfect then, would have + past participle
If I she had come to class last week, she would have known there was a quiz today.

Now for mixed conditionals!!
Watch the video from the BBC on the use and formation of mixed conditional tenses.