After months of hard work, Sarah finally decided to call it a day. What does "call it a day" mean?

To stop working on something for the rest of the day

I was going to go skydiving, but I got cold feet at the last minute. What does "cold feet" mean?

To lose your courage or become too nervous to do something

If someone tells you to "bite the bullet," what are they asking you to do?

Face a difficult situation with courage and get it over with

The new smartphone costs an arm and a leg. What does "an arm and a leg" mean?

It requires a lot of physical effort to use

My brother was supposed to keep the party a secret, but he accidentally let the cat out of the bag. What does "let the cat out of the bag" mean?