1. 任意的；随机的；偶然的
    A random sample or method is one in which all the people or things involved have an equal chance of being chosen.

random的意思

    e.g. The survey used a random sample of two thousand people across England and Wales...
           该调查在英格兰和威尔士随机抽样了2,000人。
    e.g. The competitors will be subject to random drug testing.
           参赛者将要接受随机药检。

2. 胡乱的；随便的
    If you describe events as random, you mean that they do not seem to follow a definite plan or pattern.

    e.g. ...random violence against innocent victims...
           加诸无辜受害者的无端暴行
    e.g. Children's words and actions are often fairly random.
           小孩子的言行常常是随性而为。

3. 随机地；偶然地
    If you choose people or things at random, you do not use any particular method, so they all have an equal chance of being chosen.

random

    e.g. We received several answers, and we picked one at random.
           我们收到了一些答复，并从中随机挑选了一个。

4. 胡乱地；随便地；任意地
    If something happens at random, it happens without a definite plan or pattern.

    e.g. Three black people were killed by shots fired at random from a minibus.
           3名黑人被从一辆面包车里胡乱射出的子弹打死了。