He was able to solve the complex calculation quickly.

His success had a cause-and-effect relationship with his efforts.

By learning the imperfective form, you can understand Japanese grammar more deeply.

Using exalted language in Japanese is an important way to show respect to the other person.

He is a person who never forgets to respect others.

The radius of this circle is 5 centimeters.

This computer is using the latest technology.

The Winter Triangle is a shape that connects the brightest stars in the night sky.

He drew a triangle on the blackboard.

We have maintained a good relationship for a long time.