Doublet is an important concept in linguistics.

My birthday is on the fifteenth.

I will hold my birthday party on the fifth day of the month.

He gulped down the water, perhaps because he was nervous.

This pizza is 300 kilocalories per slice.

This file has a capacity of 500 kilobytes.

He is facing multiple problems.

Let's have lunch at twelve o'clock.

I drink fresh orange juice for breakfast.

I live in Tokyo.