1. 表达;表述
    The expression of ideas or feelings is the showing of them through words, actions, or artistic activities.

    e.g. Laughter is one of the most infectious expressions of emotion...
           笑是最具感染力的情感表达方式之一。
    e.g. From Cairo came expressions of regret at the attack.
           开罗对此次攻击表示遗憾。

2. 表情;神情
    Your expression is the way that your face looks at a particular moment. It shows what you are thinking or feeling.

    e.g. The civil servant's expression, however, did not change, not so much as by a flicker...
           然而，那位公务员的表情还是那样，丝毫没变。
    e.g. Levin sat there, an expression of sadness on his face...
           莱文坐在那里，神情悲伤。

3. （表演、歌唱或演奏时的）情感表现
    Expression is the showing of feeling when you are acting, singing, or playing a musical instrument.

    e.g. I don't sing perfectly in tune, but I think I put more expression into my lyrics than a lot of other singers do.
           我唱歌不是特别合拍，但我认为我唱得比其他很多歌手都更富感情。

4. 措词;说法
    An expression is a word or phrase.

    e.g. She spoke in a quiet voice but used remarkably coarse expressions.
           她说话声音很小，但是用了些特别粗俗的字眼儿。

5. （数学中的）表达式
    In mathematics, an expression is a symbol or equation which represents a quantity or problem.

    e.g. This forms the basis for our mathematical expression for the electric field.
           这是电场数学表达式的基础。