1. Some methods to prevent soil erosion are plowing parallel with the slopes of hills, to plant trees on unproductive land, and rotating crops.
2. Chicago, is called the Windy City because of the winds coming down across the lake from Canada, is never very hot in summer.
3. Disease is not as widespread than before because of better preventive medicine and vastly improved nutrition.
4. When scientists discovered how soap works, it became possible to do synthetic detergents out of petroleum.
5. Electric telegraph, invented in 1835 by Samuel Morse, was first used in 1844.
6. Every scientist knows that gravity is the force that maintains the earth and the planets in its orbits around the sun.
7. After studying all the new materials, the student was able to rise his test score by twenty-five points.
8. Mr Anderson used to jogging in the crisp morning air during the winter months, but now he has stopped.
9. The tongue is the principle organ of taste, and is crucial for chewing, swallowed, and speaking.
10. Clare Boothe Luce wrote and productioned her first play while she was in high school.
11. Gamma globulin, a protein found in blood plasma, it is used to prevent such infectious disease as measles and viral hepatitis.
12. The plants that they belong to the family of ferns are quite varied in their size and structure.
13. Vasco da Gama, accompanied by a large crew and a fleet of twenty ships, were trying to establish Portuguese domination in Africa and India during the sixteenth century.
14. Scientists had previously estimated that the Grand Canyon in Arizona is ten million years old; but now, by using a more modern dating method, they agree that the age is closer to six million years.
15. In 1950 it was naively predicted that eight or ten computer would be sufficient to handle all of the scientific and business needs in the United States.
16. George Ellery Hale and his colleagues designed the two-hundred-inch telescope on Mount Palomar study the structure of the universe.
17. There is about 600 schools in the United States that use the Montessori method to encourage individual initiative.
18. The General Agreement on Tariffs and Trades [GATT] is an international agreement designing to increase trade among member nations.
19. J. Edgar Hoover has served as director of the FBI from 1924 until his death in 1972.
20. I put my new book of zoology here on the desk a few minutes ago, but I cannot seem to find it.