Who killed him?（貌似 Who kiiled you?比较怪,一般为不喜欢打扰死人）
比如：He was helped by his teacher.
正常语态是：His teacher helped him.
疑问句：Whe helped him?那翻译成汉语就是 是谁杀了他 他被汤姆杀了 你不觉得不舒服吗 我觉得提问应该是 他被谁杀了（那个I自动忽略吧~~）如果非要用被动语态，那就是：By whom was he killed?这是正规的语法，但人们一般不会这么说。比如：Who was his killer？Who killed him？