He gave the boy an apple改成被动语态,哪一句对a The boy was given an appleb The boy was given an apple by him为什么by him要省略

He gave the boy an apple改成被动语态,哪一句对a The boy was given an appleb The boy was given an apple by him为什么by him要省略
He gave the boy an apple
改成被动语态,哪一句对
a The boy was given an apple
b The boy was given an apple by him
为什么by him要省略

He gave the boy an apple改成被动语态,哪一句对a The boy was given an appleb The boy was given an apple by him为什么by him要省略
A是对的.
原句中没有说明是谁给男孩苹果.所以改成被动句后不用加by him

b对