【正确答案】Key points: Crowd behavior can be unpredictable because crowds have the potential for several different outcomes. Crowds have an expressive quality. Crowds show strong emotions that can be either positive or negative. Crowds can become out of control. Some crowds are organized. Demonstrations have rules for behavior, such as marching and chanting. Ho,~ever, the mood can change quickly. A crowd can have a feeling that something should be done, but uncertainty about what to do. Uncertainly may lead to breaking the rules.

【答案解析】[解析] A crowd is a temporary gathering of people who share a common focus. One interesting aspect of crowd behavior is that how the crowd ends up isn't always clear at the beginning. Crowds can be unpredictable. They have the potential for several different outcomes. For example, the crowd could just break up, or it could turn angry, or the police could break it up, or it could become a riot. Crowds have an expressive quality. They show strong emotions, and these feelings can be either positive or negative. You've probably been at events, for example, when the musicians at a concert were drowned in cheers, or, on the other hand, maybe they were booed off the stage, Maybe you've even been in crowds where emotions got out of hand, and everyone stormed the stage or tore down the goalposts. When this happens, the crowd becomes out of control. But not all expressive crowds are out of control. Some are organized into demonstrations for or against a specific goal. Demonstrations usually have their own rules for behavior-- such as marching and chanting--but they, too, can be unpredictable. The mood can change quickly, from peaceful to angry to destructive. In some crowds, there's a feeling that something should be done, but a lack of certainty about what to do. This leads to a particular mood based on that uncertainty, and finally, to a breaking of the rules. Using points and examples from the lecture, explain how crowd behavior can be unpredictable.