He made a sound of 'um' while reading the book.

This dam was built to secure the local water supply.

It's my habit to chew gum every day.

Hiromu is my best friend.

In ancient Japan, the 方相 played an important role.

As the lunar phase changes, the night sky scenery also changes.

In Japanese grammar, the passive voice is used to create a passive form.

This phase diagram shows the state of the substance.

This problem is equivalent to his ability.

In this chemical reaction, the gaseous phase plays an important role.