Some color expressions

get away with blue murder	do just what you like
once in a blue moon	something that happens very rarely
black and blue	to be physically hurt
talk till he was blue in the face	try to convince someone unsuccessfully
green (at something)	new
blue-blooded	belonging to a royal family
talked a blue streak	speak too much
out of the blue	something that comes unexpectedly
boys in blue	policemen
blue-eyed boy	someone who is a favorite
between the devil and the deep blue sea	a situation in which you can never win
felt blue	be sad
has a green thumb	the skill to grow plants
green with envy	jealous
true blue	faithful
gave the green light	said to go ahead and do it
green around the gills	feel sick or ill
the grass is greener on the other side of the fence	other people have it better