吐故纳新
get rid of the stale and take in the fresh;exhale the old and inhale the new
一个政党要～，才能保持活力。A political party can sustain its vitality only by getting rid of the stale elements and taking in the fresh.
吐故纳新tǔ ɡù nà xīn
原指人体呼吸，吐出二氧化碳，吸进新鲜空气。现多用以比喻扬弃那些不好的东西，吸收新的、好的东西。get rid of the state and take in the fresh, exhale the old and take in the new