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 was infected with hepatitis E.

He is receiving treatment for hepatitis C.

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

I repaired the broken vase using instant glue.

I love the class of reading Chinese classics in Japanese.

I studied Classical Chinese in university.

My friend goes to a Korean school.

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