The inner core of the Earth is mainly composed of iron and nickel.

He was struggling to understand his internal language.

His native language is Spanish.

This bacterium produces a powerful endotoxin.

Mr. Uchitomi is my best friend.

There is a great advantage to receiving tutoring at the teacher's home, as it allows for one-on-one instruction.

Ainai-san is my best friend.

I plan to travel to Inner Mongolia next year.

I have been to Inner Mongolia.

Mr. Yonai is my best friend.