28. Evidence suggests that one-quarter of operations _____ bypass surgery may be unnecessary.
(A) they involve
(B) involve
(C) involving
(D) which they involve

24. The first hamburgers _____ in Connecticut in 1895 by an American chef named Louis Lassen. He called them hamburgers because the sailors from Hamburg, Germany, gave him the recipe. (A) used to make and sell (B) made and sold (C) were made and sold (D) would be made and sold

25. There never seems to _____ horror stories about children neglected or abused by their parents. (A) have shortage of (B) have a shortage of (C) be a shortage of (D) are shortage of

26. Fifteen million Italians are regular smokers, but opinion polls suggest most people _____ the ban. (A) support (B) supported (C) did support (D) to support

27. Not only _____ generate energy, but it also produces fuel for other fission reactors. (A) a nuclear breeder reactor (B) it is a nuclear breeder reactor (C) does a nuclear breeder reactor (D) is a nuclear breeder reactor

29. The circuits are _____that the anthill meets all the essential criteria of an organism. (A) very intimately interwoven (B) so intimate interwoven (C) very intimate interwoven (D) so intimately interwoven

30. Chris McCandless hitchhiked to Alaska and arrived in April, 1992. He lived in a bus, and there was a bed and a stove in it. There was very little to eat—small animals, fruits and vegetables, _____ in the wild. (A) which he was finding (B) which he found (C) which he will find (D) which are to be found

31. Mr. Cooper told a journalist that he _____ a UFO because he insisted that people _____ the right to know the truth. (A) had seen; have (B) has seen; had (C) saw; had (D) sees; has

32. There is another consequence of archeology _____ more of a business than scientific research. (A) becoming (B) become (C) became (D) will become 

33. Because the supply of natural gas was plentiful in comparison to other choices like coal and fuel oil, and because it burns cleaner, many people changed their heating systems to natural gas, thereby creating shortages. Why did people prefer gas? (A) It was natural. (B) There were no other choices. (C) The other fuels were dirtier and less plentiful. (D) There is, even today, a plentiful supply of it.

34. These robust and persistent sailors gathered from all the nations of western Europe, and set out on the voyages that laid foundations for four great empires with no other power than sail and oar. Why were these voyages important? (A) Sailors came from many countries in Europe. (B) The voyages laid the foundations for western Europe. (C) The foundations for empires were established. (D) Western Europe lost its power.