String theory is a branch of physics that is a theory for understanding the basic structure of the universe.

He wrote a new paper on string theory.

He is particularly interested in string theory in physics.

Please read this instruction manual carefully before using the product.

He likes to take a walk in the park at dusk.

Einstein proposed the theory of relativity.

He is an expert in theoretical physics.

We should always remember the power of Kannon in difficult times.

General relativity is a theory of physics proposed by Einstein.

Special relativity is one of the fundamental theories of physics.