In the opinion of the author, ______ are being destroyed terribly at present.

A．The United Nations says about 50 million acres of rain forests are cut down every year.
B．Luckily people and mass media all paid special attention to the depletion of rain forests.
C．The author thought the oceans’ survival is questionable.
D．People have stopped cutting down rain forests because of the opposition of most people.

A．Louis was famous for his discovery.
B．Though his left arm and leg were disabled, he worked even harder than before.
C．In his childhood he made up his mind to become a doctor.
D．His disabled (残疾的)left arm and leg had nothing to do with the mad dogs.