- Stainless steel is an alloy of iron and chromium, or of iron, chromium, and nickel. It is practically free of the problems of rust and ordinary corrosion. It looks much like silver, but it is not nearly so expensive. Because of its low cost, resistance to tarnish, and its beauty, stainless steel has become very popular for
Your answer:
lightweight luggage.
expensive necklaces.
tableware.
copper tubing.
- Modern surgery did not develop until the nineteenth century, after the discovery of anaesthetics, antiseptics, and X rays. These three major discoveries made it possible for the surgeon to operate on a patient without causing pain, to greatly reduce the danger of infection, and to locate injuries or diseased areas
Your answer:
before surgery.
by blood tests.
during autopsies.
in the home.
- An unknown people lived many years ago along the Mississippi, Ohio, and Missouri rivers in the United States. The only traces left of these people are large earth and sand mounds. These mounds are of different shapes and sizes -- the highest is 27 meters. They contain human skeletons, pottery, weapons, pipes, ornaments, and utensils. The ornaments, pottery, and utensils have been made with great skill, which indicates that the culture of these mysterious mound builders was
Your answer:
copied.
very primitive.
considerably advanced.
unknown.
- Seawater contains almost two hundred times as much dissolved solids (salts, for example) as river water. This is true because oceans continually lose by evaporation much of the river water constantly flowing into them. Since the salts in the ocean water do not evaporate but remain behind, the oceans of the earth are gradually becoming
Your answer:
smaller.
shallower.
saltier.
heavier.
- Many holiday resorts that used to depend entirely upon summer customers are advertising skating, skiing, and other cold-weather sports. They hope to attract crowds of winter visitors and to secure for themselves
Your answer:
a better location.
teenage customers.
government assistance.
a year-round income.
- Fast aircraft make it posible to send newspapers and magazines from many countries to all parts of the world in a very short time. These publications can be read in many parts of the world on the same day that they are printed. This is an example of how aviation has aided
Your answer:
travel.
communication.
warfare.
invention.
- Competition among steel manufacturers is nothing new; but, until recently, there seemed to be a question of whose steel would be used, not a question of whether steel as such would be used. Now that functions once served exclusively by steel are being served also by light metals, concrete, or plastics, the entire steel industry is finding itself in competition with
Your answer:
individual stel companies.
steel producers abroad.
other materials manufacturing industries.
governments.
- Records of sales made on credit have been found inscribed on clay tablets from the days of ancient Babylon. Most houses, automobiles, furniture, and large household appliances are now bought on credit. Credit buying is not new, but it is much more general than it used to be. It is still used mainly for the purchase of
Your answer:
new products.
high-cost items.
insurance.
necessities.
- Penicillin, the first of the antibiotic drugs, was discovered by Sir Alexander Fleming in 1928. Some ten years after that the curative effects of penicillin on the human body were discovered. Many diseases that formerly resulted in death are now so successfully treated by antibiotics that these drugs are often called
Your answer:
miracle drugs.
modern drugs.
discoveries.
English drugs.
- Horses used to play a more important role in our economy and life. They were used for farmwork and for transport, racing, parades, exhibitions, and for riding or driving for sport. People now own cars rather than horses. With the coming of motorized farm equipment, the number of farm horses decreased greatly. Few people now own driving or riding horses. Horses are now used mainly for
Your answer:
farmwork.
family transport.
exhibition and sport.
cavalry units.