I recently met a middle school classmate of mine on the train.

He is an old acquaintance.

His knowledge is extensive, and he can talk about any topic.

There are many large turnips growing in my garden.

This ancient proverb, 'know the other side and yourself, and you will not be in danger in a hundred battles', teaches us the importance of understanding ourselves and others.

The shrine is a traditional Japanese building.

I hope our love will be eternal.

He is our class representative.

The steepest descent method is one way to solve optimization problems.

He is an expert in geophysics.