Part IV 完形填空

Like clockwork each year, starting around mid-February and peaking around mid-March through early April, hundreds of thousands of sandhill cranes fly to the Big Bend in Nebraska's Platte River. The large grey-feathered birds, known 46 the bright red skin above their eyes, a loud call that can be heard up to a mile away, and a wingspan of up to 7ft, 47 around 350 miles a day from Texas, Oklahoma or Mexico to stop in Nebraska on their way to their breeding grounds, which are spread 48 the northern United States and Canada. The sight and sound of nearly the entire population of the world's oldest living bird 49 is awe-inspiring. For the best views of the cranes, you will need to be in place 50 before sunrise, dressed in warm clothes and ready to stand quietly for about two hours. Long before you can see the birds along the river, you can 51 them. Calling to each other through the night, the birds do not ever seem to stay quiet. Amazingly, a mother can 52 her baby's call from amid the noise. When the sun starts to rise, the noise will, incredibly, 53 as all the birds begin to wake up. Without warning, or at least without one 54 you can determine, nearly an entire group, hundreds of birds, will 55 flight at once in a whoosh of wings and calls that will take your breath away. And when the early morning sunlight hits the underside of their wings, they take on a golden glow.

46. A toB ofC forD as
47. A travelB traveledC travelingD to travel
48. A overB byC throughD across
49. A membersB bodiesC speciesD songs
50. A veryB wellC reallyD hardly
51. A feelB touchC smellD hear
52. A distinguishB understandC predictD encourage
53. A disappearB changeC increaseD weaken
54. A whereB whenC whatD that
55. A getB takeC startD set