I think this prototype will be useful in developing new products.

I've reached the limit of my physical strength.

He wants to experience a primal lifestyle.

The profits of this company increase and decrease every year.

I restored the old photos digitally.

Restoring this old house will take time and effort.

This project is proceeding under rigorous supervision.

How does this pathogen infect humans?

He became distrustful of other people due to his past experiences.

Due to the impact of the new coronavirus, the number of tourists has decreased sharply.