The Conditional Tenses (If clauses)

1.I would = I´d
2.Conditional Perfect:

USE: The conditional tenses are normallu used with other tenses (conditional clauses).The elements that make this relation possible are mainly the expressions IF and UNLESS.
Ex.IF the studies he will pass the exam.(Simple Present - Simple Future)
Jack will cry UNLESS Mary gives him his pen.

IF She studied She would pass the exam.(Simple Present - Simple Conditional)
She wouln´t cry UNLESS I stole her pen.

IF he had studied he would have passed the exam.(Past Perfect - Conditional Perfect)
She wouln´t have cried UNLESS I had stolen her pen.

Observation: In the conditional clauses, WERE is used for all the persons (even the 3rd persons of singular), if we use the verb TO BE in the past.
Ex. If I WERE you, I WOULD go.
She WOULD BUY the house if she WERE you.