Read the following sentences and then choose the best synonym for each underlined word.

1. An era when polished stone implements and bows and arrows were already being used and dogs had already been domesticated.

2. There is evidence that humans hunted these elephants, as shown by numerous spear points found with mammoth remains

3. Why did the huge, seemingly successful mammoths disappear? Were humans connected with their extinction?

4. A pioneering study by Donald Appleyard made the astounding discovery that a sudden increase in the volume of traffic

5. At at that time, although they were cunning hunters, humans were still widely settled and not very numerous.

6. Abruptly, the film shifts to a scene of factory workers jostling one another on their way to a factory.

7. No one who has seen the film can ever forget Chaplin vainly trying to keep pace with the fast-moving conveyor belt.

8. This serves to illustrate people’s utter helplessness in the face of machines that are meant to serve their basic needs. 

9. Land refers to all natural resources that are usable in the production process: arable land, forests, mineral and oil deposits

10.Thus the services of a factory worker or an office worker, a ballet dancer or an astronaut all fall under the general heading of labor.

11. This obviously covers a lot of ground: factories and farms, tools and machines, transportation and communication facilities

12. Gilbert White tells how he surreptitiously removed one egg a day from a plover’s nest , and how the mother laid another egg each day to make up for the missing one.

13. He noted that other species of birds ignore the absence of a single egg but abandon their nests if more than one egg has been removed

14. Research has also shown that both mice and pigeons can be taught to distinguish between odd and even numbers of food pieces.

15. These and similar accounts have led some people to infer that creatures other than humans can actually count.

16. The potter uses one of the Earth’s most basic materials, clay. Clay can be found almost everywhere.

17. Artisans then pour on the liquid glaze and let it run over the clay surface, making any kind of decorative pattern that they want

18.The artisan who makes pottery in North America today utilizes his or her skill and imagination to create items that are beautiful as well as functional

19. Shakespeare apparently decided to take advantage of this situation and, casting off the garb of a servant

20. It is lightweight impermeable to liquids, readily cleaned and reused, durable yet.

21. As molten glass cools, it progressively stiffens until rigid, but does so without setting up a network of interlocking crystals customarily associated with that process.

22. Why glass deteriorates over time, especially when exposed to moisture.

23. why glassware must be slowly reheated and uniformly cooled after manufacture to release internal stresses induced by uneven cooling.

24. The best-known specimens are the remarkable tracks discovered at Lactoli, Tanzania, by Mary Leaky.

25. The pressures exerted along the foot, together with the length of stride, which averaged 87 centimeters, indicated that the hominids had been walking slowly.

26. The study of fossil footprints is not restricted to examples from such remote periods.

27. Apart from its low cost, the appeal of iron as a building material lay in its strength, its resistance to fire, and its potential to span vast areas.

28. Significantly, the use of exposed iron occurred mainly in the new building types spawned by the Industrial Revolution.

29. Designers of the railroad stations of the new age explored the potential of iron, covering huge areas with spans that surpassed the great vaults of medieval churches and cathedrals

30. Scholars have deciphered other ancient languages, such as Sumerian, Akkadian, and Babylonian, which used the cuneiform script, because of the fortuitous discovery of bilingual inscriptions.

31. The Rosetta stone thwarted scholars’ efforts for several decades until the early 19^th century when several key hieroglyphic phrases were decoded using the Greek inscriptions.

32. Iron production was revolutionized in the early eighteenth century when coke was first used instead of charcoal for refining iron ore.