In a way, all of us are on a spaceship, the planet Earth. We move around the sun (36) 18 miles per second and never stop. On our spaceship we have five billion people and a limited supply of air, water, and land. The (37) have to be used carefully because we can’t buy new air, water, or land from (38) else.
The environment on our planet is a closed system: nothing new is ever added. Nature (39) its resources. Water, for example, evaporates and (40) as visible drops to form clouds. This same water returns to the Earth as rain or snow. The rain that falls today is actually the same water fell on the (41) 70 million years ago.
Today, the Earth is in trouble. Factories (42) dirty water into our rivers. Many fish die and the water becomes unhealthy for people to drink. Cars and factories put poisons (43) the air and cause plants, animals and people to get sick. People throw bottles and paper out of their car windows, and the roadside becomes covered with all sorts of wastes. Over the years, people have changed the environment, and we have pollution.
To continue to (44) we must learn how to use the Earth’ s resources wisely. We have to change our (45) and stop dumping such enormous amounts of industrial waste into the water and air. We must cooperate with nature and learn better ways to use, not abuse, our environment.

36().

All forms of sales appeals that are sent through the mails are considered direct-mail advertising. The chief functions of direct-mail advertising are to familiarize prospective buyers with a product, its name, its maker, and its merits and with the product’ s local distributors. The direct-mail appeal is designed also to support the sales activities of retailers by encouraging the continued patronage of both old and new customers.
When no personal selling is involved, other methods are needed to persuade people to send in orders by mail. In addition to newspapers, magazines, radio, and television, other special devices order promotions are designed to accomplish a complete selling job without salespeople.
Used for the same broad purposes as direct-mail advertising, unmailed direct-mail advertising, includes all forms of indoor advertising displays and all printed sales appeals distributed from door to door, handed to customers in retail stores or conveyed in some other manner directly to the recipient.
With each medium competing keenly for its share of the business, advertising agencies continue to develop new techniques for displaying and selling wares and services. Among these techniques have been vastly improved printing and reproduction methods in the graphic field, adapted to magazine advertisements and to direct-mall enclosures; the use of color in newspaper advertisements and in television; and outdoor signboards more attractively designed and efficiently lighted. Many subtly effective improvements are suggested by advertising research.

A. confirm current education trends and teaching methods
B. rethink and reorganize educational strategies
C. think about the various elements which constitute what we call "communication" nowadays
D. reassure the parents about the methodology currently being used in American schools