He drew a triangle on the blackboard.

We have maintained a good relationship for a long time.

Geomorphology is the science that studies the surface shape of the earth.

Linear algebra is a branch of mathematics that studies the theory of vector spaces and linear transformations.

He has a deep interest in metaphysics.

He is an expert in statistics.

He drew a pentagon on the blackboard.

The fire alarm went off, so we immediately evacuated the building.

Genital warts are a type of sexually transmitted disease, and early detection and treatment are important.

We made a new contract.