"It's a more fundamental issue of whether or not people have the right to put out certain material in the first place."

The cooling you get when an electric current is passed through certain materials - I don't know exactly which.

"Power cannot be made to flow without certain unusual materials."

But other teachers said that current events aside, the state required them to cover certain material.

"The government shouldn't be in a position of saying you can't make art from certain materials".

This can be an advantage in understanding the physical properties of certain materials.

But the libraries may be able to restrict access to certain material.

The optical properties of certain materials allow them to be moved or held using light.

As for a ban on certain materials: of course we need one!

I can make certain old materials are available by taking more care removing them.