You need to be careful with the revolving payments of credit cards because the interest is high.

He thinks that war is a necessary evil.

Do you understand the necessity of this project?

That information is unnecessary.

That information is completely unnecessary.

He was paying attention to the teacher's talk during the class.

He broke the glass carelessly.

His carelessness caused the accident.

This issue requires attention.

He has a discerning eye, so he always chooses the highest quality wine.