DUO S20

(He contends that primitive life once existed on Mars.)

He contends that primitive life once existed on Mars.

(The crew is busy preparing for the voyage into outer space.)

The crew is busy preparing for the voyage into outer space.

(They conducted a series of experiments under zero gravity.)

They conducted a series of experiments under zero gravity.

(Many astronomers assume that the universe will expand infinitely.)

Many astronomers assume that the universe will expand infinitely.

(The astronauts were greeted with spontaneous applause.)

The astronauts were greeted with spontaneous applause.

(A fund was set up with a view to preserving our endangered planet.)

A fund was set up with a view to preserving our endangered planet.

(The massive flood paralyzed the local transportation network.)

The massive flood paralyzed the local transportation network.

(The equator divides the globe into two hemispheres.)

The equator divides the globe into two hemispheres.

(I think it's cruel to trap animals for fur coats.)

I think it's cruel to trap animals for fur coats.

(The organization plays a principal role in wildlife conservation.)

The organization plays a principal role in wildlife conservation.

(Many fragile species are on the verge of extinction.)

Many fragile species are on the verge of extinction.

(The prolonged drought did severe damage to the crops.)

The prolonged drought did severe damage to the crops.

(Tropical rain forests are quickly disappearing on a global scale.)

Tropical rain forests are quickly disappearing on a global scale.

(In part, it's due to acid rain.)

In part, it's due to acid rain.

(It is said that global warming is directly related to carbon dioxide emissions.)

It is said that global warming is directly related to carbon dioxide emissions.

(The destruction of the ozone layer affects the environment.)

The destruction of the ozone layer affects the environment.

(The committee called on all nations to work side by side to curb air pollution.)

The committee called on all nations to work side by side to curb air pollution.

(A satellite was launched into orbit to monitor melting glaciers.)

A satellite was launched into orbit to monitor melting glaciers.