happy
形容词 adj. 高兴的;满意的;满足的
还有：joyful delighted glad cheerful pleased lighthearted
但常用的是happy
例如：
1. Themselves happy, they made the others happy, too.因为他们快乐,他们也于别人快乐.
2. Happy Lunar New year! (Happy Chinese New year! )春节愉快!
3. Whoever is happy will make others happy too.快乐的人会使别人也快乐.