Bells and whistles：special features that are added to a product or system to attract more buyers

Bells and whistles：也可以表达为bells, whistles and gongs，是指某个产品不起实际作用、纯粹为了吸引顾客眼球而设计的“附加功能/特色”。可以翻译为“花哨的功能/特色；华而不实的附加特色”等。

Bells and whistles的来源：这个短语最早出现在19世纪中期的时候，科技还没那么发达，要发出响亮的声音基本上只有两种方法：摇铃或者吹哨，即Bells and whistles。铃铛和哨子不是火车的核心部分。有了它们，火车可以协调、顺畅地运转；但没了它们，火车也依旧可以前行。正因如此，bells and whistles渐渐地引申出了“非核心的附加功能/特色”之意。

参考双语例句：

Manufacturers will, therefore, still build luxury cars with all the bells and whistles but cheaper systems will be rolling down the road within the next two years.

因此，汽车制造商仍将生产配备各种花哨功能的豪华汽车，但更便宜的系统将在未来两年内问世。

And Messrs Bogle and Malkiel are right to argue that the low-cost appeal of index funds will be diluted if too many bells and whistles are added.

宝格先生和麦基尔是正确的，他们宣称如果过多华而不实的因素被加在指数基金上的话，它低成本的吸引力将被减弱。

Your website should be designed specifically for effectiveness at increasing your business, and not for bells and whistles to make it look "hip" or "cool. " So, get rid of the flash intro and all the unnecessary videos please. They really slow the site down.

你的网站设计应该专注于“有效”这一点，以便达成更 多的交易；而不应注重一些华而不实的附加特色，使它看起来很“时尚”或者很“酷”。所以，拜托你去掉动画引子和不必要的视频。它们严重影响了网站的速度。