he says he is afraid to see snake afraid怎麼使用?为什麼afraid 后面不是用of seeing,afraid to do sth.不是"不敢去做某事"吗?he says he is afraid of seeing snake这样说对吗？

afraid to do sth.是不敢去做某事"的意思
这个句子的意思就是 他不敢去看蛇
he says he is afraid of seeing snake
是 不对的
都是可以改成he says he is afraid to see the snake

be afraid to 词组 意思是 害怕做某事

be afraid of doing sth
(1) 担心会发生某事或某情况(但实际上未必会发生).如：
She was afraid of waking her husband.她怕吵醒她丈夫.
I was afraid of hurting her feelings.我怕伤害她的感情.
be afraid of doing sth 表示担心会发生某事或某情况时,其后也可用 be afraid that 替换.如：
He was afraid of losing face.＝He was afraid (that) he’d lose face.他怕失面zi.
(2) 害怕做某事或不敢做某事(指缺乏勇气或害怕其后果而不敢).如：
I’m afraid of telling her.我不敢告诉她.
He was afraid of jumping.他不敢跳.
be afraid to do sth的意思是：害怕做某事或不敢做某事.如：
He was afraid to fly in a plane.他不敢坐飞机.
He was afraid to go into the house and meet his father.他不敢进屋去见他父亲.
注：以上两类句型的异同之处：表示担心会发生某事或某情况,只能用 be afraid of doing sth,而表示害怕做某事或不敢做某事等,则两者都可用.如：
Don’t be afraid to ask [of asking] question.不要害怕问问题.
He is afraid to go out [of going out] alone at night.他不敢晚上一个人出去
综上,你那句子是表示害怕看见蛇,因此都可以用

be afraid to do 害怕做某事
be afraid of sth 害怕某物，后面大都加名词