The initial idioms of the letter K

keep up an act	keep up appearances
Keep up the good work	keep up to date
keep up	keep up with the Joneses
keep up with the times	keep (one) dangling
keep (someone) on ice	keep (one) on (one's) toes
keep watch on	keep watch over
keep weather eye open	keep with
keep within	keep within bounds
keep wits about	keep word
keep your . . .	keep your breath to cool your porridge
keep (one's) cards close to (one's) vest	Keep your chin up
keep (up) (one's) end of the bargain	keep your friends close and your enemies closer
Keep your hands to yourself	keep (one's) head below the parapet
Keep your head down	keep (one's) lips sealed
Keep your mouth shut	mind your own business