例句：

　　Laughter is one of the most infectious expressions of emotion.

　　笑是最具感染力的情感表達方式之一。

　　The civil servant's expression, however, did not change, not so much as by a flicker.

　　然而，那位公務員的表情還是那樣，絲毫沒變。

　　I don't sing perfectly in tune, but I think I put more expression into my lyrics than a lotof other singers do.

　　我唱歌不是特別合拍，但我認為我唱得比其他很多歌手都更富感情。

　　She spoke in a quiet voice but used remarkably coarse expressions.

　　她說話聲音很小，但是用了些特別粗俗的字眼兒。

　　is forms the basis for our mathematical expression for the electric field.

　　這是電場數(shù)學表達式的基礎。