I have been studying Japanese for four months.

Addition, subtraction, multiplication, and division are basic arithmetic operations.

We have been working on this project for eight months.

I lived in Japan for six months.

He was working abroad for twelve months.

He has changed so much that he is a mere shadow of his former self.

Kageyama is my friend.

He was working as a body double for a famous actor.

I saw a rhesus macaque in the park.

It is said that rhesus macaques are very intelligent.