frighten常用于be ～ed结构:其后接at, by, of或with表示被某一突然出现的人或物所惊吓; 接of还可表示习惯性地害怕某人或某物; 接介词to表示惊吓的程度。
be frightened多表示的是主语的`感觉或情绪,通常是系表结构,而不是被动结构。
例句：
Fairground rides are intended to frighten the life out of you.
露天游乐场的飞车就是想把人吓丢了魂儿。
I did not want to frighten or distress the horse.
我并不想吓到马或惹怒它。
It doesn't frighten them. They're used to it.
这可吓不倒他们。他们已经习惯了。