When you are sad or happy, it can make you forget sadness or be even happier.

在悲伤或是快乐的时候，音乐可以让人忘却悲伤或是变得更快乐。

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You never have to guess as to whether they are happy, sad, angry or indifferent.

关于他们是否快乐、悲伤、愤怒或漠然，你从不需要猜测。

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He said this study was designed to understand how changes in long-term emotional states - meaning, whether you consider yourself a happy or sad person overall - are affected by the people you know.

他表示，该研究的目的是为了了解人们的心境如何受到周围人的影响。这里的心境是指一个人大体上的情绪状态，是开心愉悦还是闷闷不乐。

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"Films are a good form of entertainment during a recession because you can sit back and -- sad or happy -- you lose where you are and you go into the movie, " she said.

CNN: Will the recession change movies?

Things like the affectionate touch to your face, the knowing smile when you do something nice for someone, the tear in their eye when you are sad or have been hurt by life, the smile when you are happy and they are sharing in it, the arms that hold you close daily.

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Some apps that Havens models his ideas on are Emotionsense, an app for Android that uses the microphone to sample the ambient sounds and conversations of the day and assembles a dossier on how happy or sad you are, and Moodscope, a website that lets users share and understand their moods and get support from friends.

FORBES: Are You Happy? An App Tries To Raise Our Collective Mood