美国人在每次过生日时，不仅庆祝年龄又大了一岁，而且也庆祝又一年过去了。因此，蜡烛既是生命和死亡的象征，也是希望和恐惧的象征。当过生日的人对着蜡烛许愿时，他/她是在祈求神的庇护以便能够交好运。当过生日的人吹熄蜡烛时，他/她则是在希望自己能掌握即将降临到自己身上的任何事情。

　　With each birthday，Americans not only celebrate growth but also the passing of another year.Thus, candles are symbols of both life and death,as well as both hope and fear.When a person makes a wish over these symbols, he or she invokes powers for good fortune. And when that person snuffs out these symbols, he or she expresses the hope to have a degree of control over whatever lies in store for him or her.来
源：考试大
小贴士来源：考试大

invoke:

(1)援用某事物为行动依据或理由

The government has invoked the Official Secrets Act in having the book banned.

政府援引国家机密保密法以禁该书。

(2)以祷告祈求某事物来源
：考试大
invoke vengeance(up)on one's enemies

求神降或祸给敌人