Idiom

a piece of cake

• it is very sweet

• It is very good but very few people know it

• it is very easy to do

hit the sack

• you win the lottery

• you give up a sport because you feel you are not good enough

• you go to bed because you are very tired

see eye to eye

• you look extremely similar to someone

• you agree with someone completely

• you are glad to see this person

break a leg

• someone injured and got his leg broken

• someone is sad because he broke his leg

• wish someone good luck

spill the beans

• tell people secret information

• drop the beans

• tell lie to someone

under the weather

• the weather is not good

• there is problem

• feeling sick

call it a day

• decide that you finish doing something

• say goodbye to someone

• call someone on the phone

the last straw

• the latest problem that makes you can't accept it/feel upset

• the last straw that you use

• it is not the problem

cost an arm and a leg

• buy something that doesn't cost much

• try to buy something with your money

• something that is really expensive

when pigs fly

• something that can't never happen

• it takes time to achieve

• something that is possible to happen