He suffered a fracture of the lesser trochanter.

He fractured his greater trochanter.

The theory of harmonic oscillators is a fundamental concept in physics.

His blood congealed with fear.

Basic oxides react with acids to produce salt and water.

This area is affected by radioactive fallout from past nuclear tests.

He can speak Min Nan.

Learning Breton language is difficult.

Learning the Erzya language is difficult.

Learning Faroese is difficult.