Answer:
A- costs an arm and a leg
B- let the cat out of the bag
C- pigs fly
D-kill two birds with one stone
E- once in a blue moon
F- under the weather
G- cutting corners
H- add insult to injury
I- Break a leg
J- speak of the devil
K- see eye to eye
L- the best of both worlds
M- you can't judge a book by it's cover
N- hit the nail on the head
O- piece of cake
Step-by-step explanation:
Idioms are basically popular sayings that have a meaning that is deeper than what is being said. For example, "speak of the devil" is not really talking about the devil but more like you see somebody you were previously talking about! That sort of thing! Well I hope this helped! :)