1. 重力；地球引力
    Gravity is the force which causes things to drop to the ground.

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    e.g. Arrows would continue to fly forward forever in a straight line were it not for gravity, which brings them down to earth.
           要不是重力使箭落向地面，它们将永远以直线往前飞行。

2. （事态的）严重性，重大
    The gravity of a situation or event is its extreme importance or seriousness.

    e.g. They deserve punishment which matches the gravity of their crime...
           应当根据罪行的严重性来惩治他们。
    e.g. Not all acts of vengeance are of equal gravity.
           并非所有的报复行为都同等恶劣。

3. （言谈举止的）庄重，严肃
    The gravity of someone's behaviour or speech is the extremely serious way in which they behave or speak.

    e.g. There was an appealing gravity to everything she said.
           她说的每句话都带着一种庄严，很能吸引人。