A、External conditions. B、People’s internal conditions influenced by physical or mental factors. C、Slippery roads. D、A chain of e

Accidents are caused; they don’t just happen. The reason may be easy to see: an overloaded tray, a shelf out of reach, a patch of ice on the road. But more often than not there is a chain of events leading up to the misfortune—frustration, tiredness, or just bad temper—that show what the accident really is, a sort of attack on oneself.
    Road accidents, for example, happen frequently after a family quarrel, and we all know people who are accident-prone, so often at odds with themselves and the world that they seem to cause accidents for themselves and others.
    By definition, an accident is something you cannot predict to avoid, and the idea which used to be current, that the majority of road accidents are caused by a minority of criminally careless drivers, is not supported by insurance statistics. These show that most accidents involve ordinary motorists in a moment of carelessness or thoughtlessness.
    It is not always clear, either, what sort of conditions made people more likely to have an accident. For instance, the law requires all factories to take safety precautions and most companies have safety committees to make sure that the regulations are observed, but still, every day in Britain, some fifty thousand men and women are absent from work due to accidents. These accidents are largely the result of human error or misjudgment—noise and fatigue, boredom or worry are possible factors which contribute to this. Doctors who work in factories have found that those who drink too much, usually people, who have a high anxiety level, run three times the normal risk of accidents at work.