"多少蜡烛" 的英语表达是 "how many candles"。其来源是出自日常生活中的问候语，用来询问对方的年龄。
例句：
"How many candles are on your birthday cake?" (你的生日蛋糕上有多少蜡烛?)
"I can't bepeve you're already 30, how many candles were on your cake?" (你已经30岁了，蛋糕上有多少蜡烛?)
类似的表达还有：
"How old are you?" (你多大了?)
"What's your age?" (你多大了?)