He has a short fuse
He gets mad/upset easily
She is feeling under the weather
She is feeling sick
He let the cat out of the bag
He told a secret
He is off his rocker
He is acting weird or silly
It was a piece of cake
It was easy
To miss the boat on that one
to miss an opportunity because you acted or responded to slow
They don't see eye to eye
They don't agree
She pulled the wool over my eyes
She tricked or deceived me
Don't cry over spilled milk
It will cost an arm and a leg
It will be expensive
to hear it through the grapevine
to hear a rumor or get information from a friend who got it from a friend
He always steals her thunder
He always takes credit/praise for something she did, or he always takes the attention away
They went back to the drawing board
When you need to come up with a new idea or plan for something
Don't judge a book by its cover
Don's make an assumption about someone or something based on how it looks, or without knowing the whole situation
To have butterflies in your stomach
to be nervous about something
The ball is in your court
Its your turn to make the next move or make the next decision
It takes two to tango
He was beating around the bush
When you don't want to talk about something so you talk about random or unimportant things
Don't count your chickens before they hatch
don't be too confident in anticipating success or good fortune before it is certain
kill two birds with one stone
Accomplish two things at once
He is barking up the wrong tree
He is telling/complaining to the wrong person
Take the story with a grain of salt
To not believe it completely
He bit off more than he can chew
Agreed to do something that was too hard or that you don't have time to do
To deal with something when we need to or when it happens
hit the nail right on the head
to do or say something that is exactly right