My new bicycle is very fast.

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

He learned how to operate the anti-tank gun.

His efforts were like a mantis trying to stop a chariot, he couldn't achieve any results.

He is attending school to obtain a motorcycle license.

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.