新陈代谢the new replaces the old (metabolism in biology)

信口开河empty promises;to talk off the cuff

心口如一to be frank and unreserved;honest and straightforward (lit. heart and mouth as one)

欣欣向荣luxuriant growth;flourishing;thriving

心直口快frank and outspoken;to say what one thinks

兴高采烈happy and excited;in high spirits;in great delight

兴致勃勃to become exhilarated;in high spirits;full of zest

悬崖峭壁sheer cliffs and precipitous rock faces

雪上加霜to add hail to snow;one disaster on top of another;to make things worse in a bad situation

雪中送炭timely assistance (lit. to send coal during snow)