1. Birds all over the world ………………… in distances up to thousands of miles.

2. Cellulose, which ………………… for making paper, can be found in all plants.

3. …………………, human beings have relatively constant body temperature.

4. So far there is no vaccine …………………in sight for the common cold.

5. The Louisiana Territory, an area ………………… the size of France, was bought by the United States from France for $15,000,000 in 1803.

6. Despite claims that filters and low-tar tobacco make smoking somewhat safer, in fact they only marginally reduce…………………eliminate, the hazards.

7. …………………many of the designs for the new capital were considered lost forever, Benjamin Banneker helped reproduce the original plans.

8. A few natural elements exist in …………………that they are rarely seen in their natural environments.

9. Generally speaking, every person…………………the potential to be a teacher, to some extent.

10. …………………business, a merger is a combination of two or more corporations under one management.

11. …………………of commodities by air began in the 1920s at the same time as airmail service.

12. Jan Malzeliger’s invention, the “shoe-lasting” machine, …………………production but it also cut the cost of shoe production by half.

13. It can sometimes …………………a home.

14. Jellyfish are probably …………………on Earth.

15. In the United States …………………is the most concentrated is New Orleans.

16. In 1931 Jane Addams was a Nobel Peace Prize recipient for she humanitarian achievements.

17. Even on the most careful prepared trip , problems will sometimes develop.

18. Many people say that California is a state of geographic remarkable diversity.

19. An uncultivated tea plant might grow about 30 feet height.

20. A galaxy, where may include billions of stars, is held together by gravitational attraction.

21. Rocks can be broken apart by water that seeps into the cracks and freeze in low temperatures.

22. Alexander Graham Bell was once a teacher who run a school for the deaf in Massachusetts.

23. Some fish use their sense of smell as a guide when return to a spawning site.

24. In Quebec, Canada, the flowing of the maple sap is one of the first sign of spring.

25. Antique auctions are getting more and more popular in the United States because increasing public awareness of the value of investing in antiques.

26. Archaeological evidence reveals that Native Americans lived on the East Coast of the United States 13 centuries before.

27. Diamond itself is the only material hard enough to cut and polishes diamonds.

28. The change from day to night results the rotation of the Earth.

29. As Ingrid Bergman lived a life of courage, she also approached die with courage.

30. Residents in some cities can call an electrical inspector to have the wiring in their house is checked.

31. The best way to eliminate a pest is to controlling the food accessible to it.

32. The Earth depends the sun for its heating.

33. The famous aviator Charles Lindbergh was a early supporter of rocket research.

34. Cholesterol help the body by making hormones and building cell walls, but too much cholesterol can cause heart problems.

35. Luther Burbank was a pioneer in the process of graft immature plants onto fully mature plants.

36. With its compound eyes, dragonflies can see moving insects approximately 18 feet away.

37. An X-ray microscope enables a person to see on solid materials such as metal and bone.

38. The United States has a younger population as most other major industrial countries.

39. Before the invention of the printing press, books have been all printed by hand.

40. As the Asian economic miracle spreads throughout the Pacific, wage increases everywhere is affecting millions of consumers.