He is a very quiet person.

His actions are showing a portent of danger.

Let's put the leftover food in the refrigerator.

Jou changed his clothes and went out.

It is said that secondhand smoke has a negative impact on health.

Topology is a branch of mathematics that abstracts and generalizes the concept of space.

He has already finished writing the report, so we use the present perfect form.

He was infected with hepatitis E.

He is receiving treatment for hepatitis C.

Hepatitis D is a viral disease that is transmitted through blood.