过生日的时候一般都少不了长寿面，蛋糕，礼物，还有跃舞跳动的一根根彩色蜡烛。可是，好好一个完整的蛋糕上面干吗要插那些蜡烛呢？

Thousands of years ago birthdays were considered a time when the bad spirits as opposed to the good spirits were able to harm you as this day changed a person's life. It was believed that the only way to keep the bad spirits at bay was to have your friends and family around you so that their good wishes and present giving would keep them at bay.

Also noisemakers are thought to be used at parties as a way of scaring away the evil spirits.

The custom of lighting candles originated with people believing that the gods lived in the sky and by lighting candles and torches they were sending a signal or prayer to the gods so they could be answered. When you blow out the candles and make a wish, this is another way of sending a signal and a message.

The candles in the cake represent life, burning brightly for a short time and then snuffed out. The person blowing out the candles is saying, "This much of my life is over -- I'll never get it back, but I still have the breath of life within me and I am in control. I will blow away the past and start anew with this wish."

（来源：rootsweb.com 英语点津 Helen 编辑）