将下列英文短语翻译成中文。
“break a leg”、“give someone a hand”、“let the cat out of the bag”、“hit the nail on the head”、“costs an arm and a leg”
"break a leg" - 祝好运
"give someone a hand" - 帮助某人
"let the cat out of the bag" - 泄露秘密
"hit the nail on the head" - 正中要害
"costs an arm and a leg" - 代价高昂