He is researching artificial humans.

My father underwent surgery for kidney stones.

This dress is made of rayon.

This dress is made of rayon.

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.