根本

Water and soil are the foundation of agriculture.

Since I was a child, my mother has told me that honesty is the foundation of being a human being.

The problem must be solved at its root.

Education is the fundamental plan for the development of the country and the nation.

The fundamental cause of the development of things must be found inside things.

The problem has been fundamentally solved.

This unhealthy climate has fundamentally changed.

I had no idea about it.

He didn't take it to heart at all.

We hadn't been in this situation before, so we weren't prepared.

You're not right at all!

I ignored him at all.