let.down
n.(名词)A decrease, decline, or relaxation, as of effort or energy.放松,弛缓,衰落:努力或力量方面的减少、降低或放松A disappointment:失望、沮丧:例句:The cancellation of the game was a real letdown.比赛取消真是令人失望
The descent made by an aircraft in order to land.飞机的程序下降:飞机为了着陆而作的下降飞行