祝生日快樂的英文祝福有很多種形式，可以根據不同的關係和場合選擇合適的祝福語。以下是一些示例：
Happy birthday! 生日快樂
Many happy returns of the day! 生日快樂
Wishing you a wonderful birthday. 祝你有一個棒極了的生日
May your birthday and all the days to come be filled with happiness. 願你的生日以及未來的日子充滿幸福
Happy birthday to a marvelous friend. 祝我的了不起的朋友生日快樂
May your birthday be filled with smiles, sunshine, love, and laughter. 祝願你生日這一天充滿快樂、陽光、關愛和笑聲
I wish you nothing but the best on your special day. 在這特別的一天祝願你一切都好
Wishing you a super time on your birthday. 祝你生日過得超級開心
Thinking of you on your special day. 在想你特別的日子裡