This expressions is used when someone isn't saying anything.
what is cat got your tongue?
Someone who is very lazy
What is couch potato?
Unaware of what is going on because you are daydreaming
What is head in the clouds?
To tell someone "good luck"
What is break a leg?
Raining very hard
what is raining cats and dogs?
Cherished above all others
What is the apple of my eye?
Not healthy
What is under the weather?
To be scared to do something
What is cold feet?
Something that will never happens
what is when pigs fly ?
Complain about something you can not change
What is cry over spilled milk?
In a risky situation
What is on thin ice?
Listening carefully to what someone is saying
What is all ears?
The last in a series of unpleasant events which finally makes you feel that you cannot continue to accept a bad situation
what is the last straw?
Driving a car that is defective or doesn't work well
What is drive a lemon?
Being too old for something
What is over the hill?
Very expensive
What is cost an arm and a leg?
To solve two problems at one time with a single action
What is kill two birds with one stone?
Two of a kind : very similar
What is two peas in a pod?
To be in a dangerous or risky situation
What is out on a limb?
To be overly emotional and not thinking straight
What is lose your head?