Idioms

When pigs fly..

•  Something true
• Something that will never happen
• Something related to flying

Let the cat out of the bag

• Free a cat
• Keep a secret
• Reveal a Secret 

Zip your mouth!

• Say something
• Keep your mouth shut and don´t say anything
• Speak loud

A piece of cake 

• Something very easy to do
• Something really hard to do
• Dessert

Cash cow

• A cow with much money
• A good way to make money
• A cow

Whole bag of tricks ..

• Trying all the clever means to achieve something.
• Do not try anything
• Use tricks

Once in a blue moon...

•   An event that happens frequently
• An event that happens infrequently.
• A blue moon

Explore all avenues

• To visit all the avenues
• To know the city
• Trying out every possibility to get a result.

Break a leg

• good luck
• back luck 
• a broken leg

Speak of the devil

• Talk about someone bad
• means that the person you’re just talking about actually turns up at that moment
• It means that the person you're talking about does not show up at that time.