简单一点的，朋友看得懂：Happy birthday to you!Best wishes!
复杂一点的：
【祝福：NO.01】——《友情篇》
From majestic mountains and valleys of green to crystal clear waters so blue, this wish is coming to you.
越过青翠的峻岭和山谷，直到晶莹湛蓝的水边，飞来了我对你的祝愿。
【祝福：NO.02】——《爱情篇》
You're everything to me.
你是我的一切。
【祝福：NO.03】——《慰问篇》
Though words cannot express the thoughts the heart would like to say, still may you know that others care and sympathize today.
虽然言语不能表达内心欲诉的哀愁，
仍愿你知道朋友们今天都为你分忧。
【祝福：NO.04】——《朋友生日篇》
Every day is birthday time when thinking of you,
and I shall keep one sublime
hoping your many dreams come true.
每当想到你我好似天天都在过生日，
可我特别珍视其中的一天，
祝愿你在这天美梦都能实现。
【祝福：NO.05】——《心上人生日篇》
Happy birthday to an attractive, intellectual, sophisticated and all round splendid person.
祝福一位美丽迷人，聪明大方，成熟端庄，又倍受赞叹的妙人儿，生日快乐。
【祝福：NO.06】——《祝爷爷、奶奶生日篇》
You know you're thought of lovingly each day throughout the year.
But it's nice to mention it again when special days are here.
您知道我们无日不把你亲切思念，
逢寿辰当然要把这话再说一遍。
【祝福：NO.07】——《祝父亲、母亲生日篇》
Only wishes that are made with special love will do
for a dad who is wonderful in every way as you.
只有用挚爱绢成的祝福的话，
才能献给像您那样慈爱的爸。
【祝福：NO.08】——《祝伯、叔、姑、姨生日篇》
It's fun to send these wishes for an especially happy to an uncle who is nice in every way.
在特别欢乐的一天，给完美无缺的伯父祝寿，真叫我喜悦满心间。
【祝福：NO.09】——《祝兄弟、姐妹生日篇》
As a brother, you're the greatest, but your good points don't stop there.
As a person and friend, you're the nicest anywhere.
作为哥哥，你最伟大，你的优点还有不少，
作为一个和朋友，不论在哪一方面你都最好。
【祝福：NO.10】——《祝儿子、女儿生日篇》
It's so easy to be proud of a son like you.
Happy Birthday!
有你这样的儿子，怎能不感到骄傲，生日幸福！
【祝福：NO.11】——《祝侄儿、侄女生日篇》
You've always been so special and so warmly thought of, too, that it's really for you.
因为你一向这样聪明可爱，又这样叫人牵肠挂肚，所以这张贺卡真是非你莫属！
【祝福：NO.12】——《祝贺1—10岁小孩生日篇》
Here's hoping that your special day is such a happy one,
You're sure to say "my goodness, but a birthday is lots of fun."
愿你的生日特别快乐，
你准会说："天哪，过生日真叫人乐呵呵！"
【祝福：NO.13】——《贺新年篇》
May warmest wishes, happy thoughts and friendly greetings come at Christmas and stay with you the whole year through.
愿温馨的祝愿、幸福的思念和友谊的祝贺在圣诞佳节来到你身边，伴随你整整一年
【祝福：NO.14】——《感谢篇》
It is at a time like this that one really appreciates the kindness of a friend.
只有在这样的时刻，一个人才会真正领略到朋友的深情厚意。
【祝福：NO.15】——《成功篇》
Your honor brings to all of us.
你的荣誉给我们带来了荣耀。
【祝福：NO.16】——《婚庆篇》
Only once in a lifetime that a special dream comes true.
And suddenly your entire world seems beautiful and new.
Best wishes always!
一生中只有一次美梦实现的奇迹，你俩的整个世界顿时变得绚丽新奇。
祝永远幸福！
【祝福：NO.17】——《健康篇》
A great big wish that you'll soon be back in tip-top condition.
深深地祝愿你早日痊愈，健康无与伦比！
【祝福：NO.18】——《一般祝愿 Wishes》
This extra special "Bon Voyage" comes to you to say hope you sill enjoy your trip in every kind of way.
向你说一声格外亲切的"一路平安"，
愿你心情享受旅途的愉快，
事事顺心，心儿舒展。
摘自『百度知道』
