参考答案

正确答案：A
解析：选项A“少有的，不同寻常的，非同一般的事件，暴力事件”(An event，especially one that is unusual，important or violent)，例如：A spokesman said it was an isolated incident．Am I at risk because of some incident in the past? 选项B“偶然事件，突发事件”(sth that happens without anyone planning or intendi