When you try not to do something, you say that you avoid doing it, not that you 'avoid to do it'. This leaflet tells you how to avoid getting ill. If you want to suggest that you cannot stop yourself from doing something, you should use the expression can't help. I'm sorry, I can't help being suspicious... Nobody liked her to cough, but she couldn'thelp it. If you prevent something, you do something to ensure that it does not happen. They must take urgent action to prevent a famine. If you prevent accidents or diseases, you stop them from happening. If you avoid accidents or diseases, you succeed in not having them or catching them. ...a rope that prevented her from falling. ...a sound recommendation for avoiding cancer. Note that you do not use prevent when telling people about danger. The word you use is warn, and you can warn people about or of a danger. You can also warn them that something is happening or warn them to do something. I warned her about the hole in the floor... She warned me to stay away.

当表示避免做某事时，用avoid doing it, 不能用avoid to do it。例如：This leaflet tells you how to avoid getting ill（这个小册子指导人们如何预防疾病）。如果想表示情不自禁地做某事，用短语can't help。例如：I'm sorry, I can't help being suspicious（对不起，我忍不住要表示怀疑），Nobody liked her to cough, but she couldn't help it（大家都不希望她咳嗽，但她忍不住）。prevent意为防止某事发生，例如：They must take urgent action to prevent a famine（他们必须立即采取行动预防饥荒）。prevent后接事故或疾病，表示防止其发生。avoid后接事故或疾病，表示成功地避免受影响或感染。例如：a rope that prevented her from falling（让她不至于摔倒的绳子），a sound recommendation for avoiding cancer（预防癌症的合理建议）。注意，在告诉别人有危险时，不用prevent，而用warn。警告某人某事要发生或告诫某人做某事也可用warn。例如：I warned her about the hole in the floor (我提醒她地上有个洞), She warned me to stay away (她警告我离远点儿)。