happiness n.幸福，高兴，恰当，合适
happy： 英 [ˈhapi]美 [ˈhæpi] adj. （感到或显得）愉快的，高兴的；幸福的，美满的；〈非正式〉滥用…的，胡乱使用…的
例句：
Melissa came in looking happy and excited 梅利莎进来时显得又高兴又激动 [with
clause]we're just happy that he's still alive 我们十分高兴他还活着
with infinitive]they are happy to see me doing well. 他们看到我进展顺利很是高兴。
happiness 例句：
Do not wait for good things to happen to you. You need to walk towards happiness. 不要等待好事降临，你要向幸福进发。
Remember, happiness doesn't depend upon who you are or what you have; it depends solely upon what you think.--Dale Carnegie 请记住，幸福不在于你是谁或者你拥有什么，而仅仅取决于你的心态！
The secret to happiness is to keep setting yourself new challenges. 幸福的秘诀就是要不停地给自己设定新的挑战。