This rain, like merciful rain in a drought, really helped the farmers.

This region had been suffering from a long drought, but finally, the merciful rain in a drought fell.

I learned the theory of commutative rings at university.

He is an expert in ring theory and has written many papers in the field.

He was diagnosed with liver cancer.

My grandmother has been suffering from arthritis for many years.

He likes to read picaresque novels.

I learned about casein in biochemistry class.

It was found out that he is suffering from fascioliasis.

The sheep liver fluke is a parasite that lives in the liver of sheep.