There are many different sorts of flowers in the garden.

The lovers engraved the oak tree with their initials.

I attended a lecture on artificial intelligence.

The passenger boarded the plane.

The hikers reached the peak of the mountain after a long and challenging climb.

The train runs on the rail.

Theoretical physics is a branch of science that deals with the fundamental principles of the universe.

You are absolutely right.

The bird flew above the trees.

Symbols can represent complex ideas.