They are my best friends.

He opposed the plan.

This area has active convection, causing frequent thunderstorms.

The dialogue with him is always fun.

This object is the focus of my research.

He is good at writing antithetical couplets.

This is absolutely without a doubt.

I can't forget the day when I first shared an umbrella with him.

Water turning into ice is an example of a phase transition.

We are looking for new partnerships to strengthen our business contact.