Kiyasu is my best friend.

Tomoki is my best friend.

I have been to Keelung City in Taiwan.

My child attends a supplementary school every Saturday.

He understands the meaning of the proverb 'Teaching is half learning', which means that teaching leads to one's own learning.

Stoichiometry is a method for calculating the amount of substances in a chemical reaction.

Chemotransmitters play an important role in the transmission of information between nerve cells.

No chemical flavoring is used in this ramen at all.

My company specializes in the manufacture of fine chemicals.

The concept of chemical equivalent is essential for understanding chemical reactions.