by himself在句子中做什么成分?

题目

by himself在句子中做什么成分?
The building shall be constructed by himself.
上句中的by himself 在句中做什么成分?
还有一句话“He has the ability to do the work."
变成疑问句是”Has he the ability to do the work?

答案

by himself作状语
Has he the ability to do the work?
Does he have the ability to do the work?