1. When pigs fly - an event which is highly impossible to happen.

I'll pass that test when pigs fly.
Meaning: It is highly impossible to pass that test.

2. Baker's Dozen - thirteen.

Can I have a baker's dozen of cookies?
Meaning: The person is asking for thirteen pieces of cookies.

3. Dead Ringer - identical.

I'm very sure that this is a dead ringer of my work.
Meaning: The person is sure that his work is identical to another person's work.

4. Pig out - to eat a lot and to eat very quickly.

You sure do pig out very often.
Meaning That person eats a lot and very quickly often.
Lend Me Your Ears
⇒The teacher said to her pupils to lend the ears of her pupils.