What on earth is he thinking?

This substance will change into a solid.

This liquid is very dangerous.

This medicine is made outside of the body.

The depressed cowry lives quietly at the bottom of the sea.

Linear programming is a part of operations research and is used to find the optimal solution.

Paying the urban planning tax is a citizen's duty.

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

There was a spot on his shirt.

I have been to Ahmedabad.