Happy as a clam即“非常开心或满足”，形容一个人非常快乐和满足，通常是因为他们正在做自己喜欢的事情或者处于一个愉快的环境中。

Happy as a clam完整版本是：happy as a clam at high tide/water，最早出现在19世纪初期。到了19世纪30年代，后面的at high tide/water部分被省略，短语正式变为happy as a clam，流传至今。

Happy as a clam的来源：Low tide（低潮）使蛤蜊很容易在沙滩上现身，人们发现、挖走它的几率也就大大提高。而high tide（高潮）可以让蛤蜊安安稳稳被水覆盖着，不用担心突然有人把它从沙滩上掳走。所以它在high tide的时候自然是很开心的。

Sonnet to a Clam《致蛤蜊的十四行诗》——John G.Saxe

Thy life is one of very little ease;（你的生活其实充满了艰辛；）

Albeit men mock the e with their similes,（尽管人们用比喻来嘲弄你，）

And prate of being“happy as a clam！（胡扯什么“像蛤蜊一样开心！)

参考双语例句：

As my mom always says, feeding me is as easy as it gets . Fix some tofu every meal, and I'll be happy as a clam.

我妈总是说，养活我再容易不过了。只要每一餐都有豆腐，我就会很开心。

Kevin is a typical family man. As long as he gets to spend some quality time with his wife and kids on weekends, he 'll be happy as a clam.

Kevin是典型的家庭型男人。只要每个周末能和妻子、孩子们好好相处一段时间，他就十分开心了。