Decide which of the choices given below would correctly complete the passage if inserted in the corresponding blanks. Mark the correct choice for each blank on your answer Sheet.
　　Our ape-men forefathers had no obvious natural weapons in the struggle for survi val in the open. They had neither the powerful teeth nor the strong claws of the big cats. They could not ( 26 ) with the bear, whose strengt h, speed and claws ( 27 ) an impressive ’small fire’ weaponry . They could not even defend themselves ( 28 ) runnin g swiftly like the horses, zebras or small animals. If the ape-men h ad attempted to compete on those terms in the open, they would have been ( 29 ) to failure and extinction. But they were (30) with enormous concealed advantages of a kind not possessed by any of the ir competitors.
　　In the search ( 31 ) the pickings of the forest, the ape-men had ( 32 ) efficient stereoscopic vision and a sense of colour that the animals of the grasslands did not possess. The abili ty to see clearly at close range permitted the ape-men to study practical proble ms in a way that lay far ( 33 ) the reach of the original inh abitants of the grassland. Good long-distance sight was ( 34 ) another matter. Lack of long-distance vision had not been a problem for fores t-dwelling apes and monkeys because the higher the viewpoint, the greater the ra nge of sight—so ( 35 ) they had had to do was climb a tree. Out in the open, however, this simple solution was not ( 3 6 ) . Climbing a hill would have helped, but in many places the gro und was flat. The ape-men ( 37 ) the only possible solution. They reared up as high as possible on their hind limbs and began to walk upright . This vital change of physical position brought about considerable disadvantages. It was extremely unstable and it meant that the already slow ape-men became slo wer still. ( 38 ) , they persevered and their bone structure gradually became ( 39 )猼o the new,unstable position that ( 40 ) them the name Homo erectus,upright man.
　　26. A. match B. compare C. rival D. equal
　　27. A. became B. equipped C. posed D. provided
　　28. A. in B. upon C. by D. with
　　29. A. driven B. doomed C. forced D. led
　　30. A. bestowed B. given C. presented D. endowed
　　31. A.for B. of C. on D. at
　　32. A. progressed B.generated C.developed D.advanced
　　33. A.from B.apart C. beyond D.above
　　34. A. rather B.quite C. much D.really
　　35. A. anything B.that C. everything D.all
　　36. A. available B.enough C. sufficient D.convenient
　　37. A. chose B.adopted C. accepted D.took
　　38. A. However B.Therefore C. Meanwhile D.Subsequently
　　39. A. accustomed B. familiarized C. adapted D. suited
　　40. A. obtained B.called C. deserved D. earned