一直快乐用英语怎么说

"Always be happy" 的英文表达是 "Always keep a smile on your face" 或 "Always maintain a positive attitude"。这是一种倡导积极心态的格言。

来源：这句话源自于英文谚语“A smile is a curve that sets everything straight”，意思是微笑是能够抹平一切的曲线。

例句：

"Always keep a smile on your face, even in difficult times."
(即使在困难时刻也要保持微笑)
"Maintaining a positive attitude is key to happiness. Always remember to keep a smile on your face."
(维持积极的态度是幸福的关键。记住要保持微笑)