He seems to be enjoying his idleness.

His family's crest tells the story of ancient history.

He cannot read the letter because he is illiterate.

He found a solution to the problem through a cycle of answering his own questions.

He found a solution by repeatedly answering his own questions.

He is a specialist in that field.

He studied under a famous painter.

The family crest of my house is Nantenmon.

My new coat hanger is very convenient.

He couldn't say anything about issues outside of his field of expertise.