Mistake 在这里是动词,意思是:误会,误解.I mistake his intentions 意思是:我误会他的意图了.而be mistaken about sb/sth意思是:对某事持错误的见解/看法.这里mistaken是形容词,不表示被动.I mistake his intentions=I am mistaken about his intentions.You are mistaken about Jane=You mistake Jane.I mistake his intentions 变成被动语态应该是:His intentions are mistaken by me.类似动词还有:worry about,be worried about