They are my best friends.

He has been working as a doctor in this town for many years.

I haven't seen him for a long time.

He has been working as a doctor in this town for many years.

We have built a close relationship.

Their closeness is the result of years of collaboration.

The results of the exam are out.

Years of effort finally bore fruit.

We started cooperation for a new project.

We cooperated to make the project successful.