既往不咎，忘掉旧嫌的英文：
let bygones be bygones

let是什么意思：
v. 允许；让；假设；出租
n. 擦网球

Let it be as you desire.
就按照你的意思办吧。

Let in sheathing.
镶进夹衬板。

He let go of the pole and let it fall.
他松开那根柱子，让它倒下了。

Let's go to the theater.
我们看戏去吧。

Let's cut for dealer.
让咱们切牌来决定由谁先发牌吧。

bygones是什么意思：
adj. 很久以前的；以往的

Don't mention it. Let bygones be bygones.
别再提它了。过去的事就让它过去吧。

Let bygones be bygones. We're still friends.
让过去的事过去吧。我们还是好朋友

You ought to let bygones be bygones and not worry about it anymore.

This writer has a power of contemporizing himself with the bygone times
这位作家能把古代写得栩栩如生。

It is not advisable just to sit there Brooding about the unpleasant Bygones.
老是坐在那里闷闷不乐地想着过去那些不愉快的事情并不好。