work one's fingers to the bone(Slavik_K); beat one's brains out(I've been beating my brains out trying to get a passing grade this semester. • Don't beat your brains out trying to please these people – they'll never appreciate it. • Why should I beat my brains out for a corporation that knows me only by a number – takes my life in, chews it up and spits it out.4uzhoj); try hard(Abysslooker); fall over oneself(Governments were falling over each other to win these valuable contracts • The idiots were all falling over themselves to buy his second-hand carsTaras); be falling over oneself(Taras)