在一定条件下,可能发生也可能不发生的事件叫随机事件(有时也叫可能事件),一定会发生的事件叫必然事件(有时也叫确定事件),一定不发生的事件叫不可能事件.对事件发生可能性的思考,可以帮助人们作出合理的推断和预测,现举两则趣题,供同学们欣赏.例1学校门口经常有小贩搞摸奖活动,某小贩在一只黑色的口袋里装有仅颜色不同的50只小球,其中红球1只,黄球2只,绿球 Under certain conditions, events that may or may not occur are called random events (sometimes called possible events), events that must happen are called inevitable events (sometimes called definite events), and events that do not happen are called impossible events. Thinking of the possibility of an incident can help people make reasonable inferences and predictions, we now give two tips for students to enjoy.Example 1 There are often hawkers at the school gate to get lucky prize activities, a peddler in a black pocket There are only 50 balls with different colors, including 1 red ball, 2 yellow balls and green ball