feel down in the mouth	feel discouraged/depressed być zniechęconym, zdołowanym
get a move on	hurry up /pospiesz się
work a miracle	make sth almost impossible happen/uczynić cud
slip one's mind	forget about sth/wylecieć komuś z pamięci
put words into one's mouth	pretend that sb had said sth, while it is not truth/ wkładać komuś słowa w usta
make hay while the sun shines	take adventage of favourable circumstances
cry over spilt milk	grieve over sth that can't be put right
give the green light to sth/sb	give permission
cross one's mind	have a sudden idea
a night owl	person who enjoys staying up late
in a nutshell	briefly
have an early night	go to bed early
be second to none	be the best
hit the nail on the head	say exactly the right thing/ trafić w sedno
lose one's nerves	lose courage
null and void	invalid/bez mocy prawnej
every nook and cranny	everywhere
make a name for oneself	become famous/respected
get on one's nerves	annoy sb