So, lock the door and throw out the key

那么就锁上房门吧钥匙扔掉便是

throw out拒绝，否决； 提出（暗示、建议等）； 掷出； 赶下台

例句：

Throw out a minnow to catch a whale.

弃小引大.

54 Don't throw out the baby with the bath water.

54切勿好坏不分一起抛.

Throw out that waste paper.

把废纸扔掉.

But you never let medown

但你未曾让我失望过

Let down放低； 放下； 使失望； 失信

例句：

Sadly, the film is let down by an excessively simple plot.

遗憾的是，过于简单的情节使得这部电影令人失望。

He let down the tailgate so the dog could jump out.

他放下后背门，好让狗跳出来。

But then to be let down like that, oh it's so unfair!

但是接下来竟让人如此失望，唉，这真不公平！