Old English is a language that was spoken in England from the 5th to the 12th century.

A diagonal matrix is a matrix in which all elements outside the main diagonal are zero.

The diagonal elements of this matrix are all 1.

His shoes are a symmetrical pair, perfectly matching left and right.

He made a seven pairs in mahjong.

We need to evaluate the cost-effectiveness of this project.

We need to evaluate the cost-effectiveness of this project.

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

We should always remember the power of Kannon in difficult times.

He always keeps in mind the phrase 'If one learns without thinking, it is a waste.'