Foreign language teaching is ______ art as well as ______ science.

A．it's bad for all living things in the world
B．it makes much noise
C．it makes our rivers and lakes dirty
D．it makes us angry more easily

A．Many countries are making rules to fight pollution.
B．The pollution of the earth grows as fast as the world's population does.
C．If people could go to work by bus or bike instead of car or motorbike it would be helpful in fighting against the problem of SO₂.
D．The problem of pollution is not so serious because there are not so many people living on the earth.