The Mesolithic is the era between the Paleolithic and the Neolithic.

The Riemann sum is a method for approximately calculating the integral of a function.

I stabbed the needle for the injection.

Karen bought a rose at a flower shop.

The United Nations Environment Programme is providing solutions to global environmental problems.

He was feeling loneliness.

He provided a detailed explanation to elucidate the issue.

This job is suitable for him.

He is suffering from acute leukemia.

He contracted severe invasive streptococcal disease and underwent emergency surgery.