第6部分：完形填空(第51～65题，每题1分，共15分)
阅读下面的短文，文中有15处空白，每处空白给出了4个选项，请根据短文的内容从4个选项中选择1个最佳答案，涂在答题卡相应的位置上。
Highways in the United States
The United States is well-known for its network of major highways designed to help a driver get from one place to another in the shortest possible time. __51__ these wide modern roads are generally __52__ and well maintained, with few sharp curves and __53__ straight sections, a direct route is not always the most __54__ one. Large highways often pass __55__ scenic areas and interesting small towns. Furthermore, these highways generally __56__ large urban centers which means that they become crowded with __57__ traffic during rush hours, __58__ the "fast, direct" way becomes a very slow route. However, there is almost always another route to __59__ if you are not in a hurry. Not for from the relatively new "superhighways", there are often older, __60__ heavily traveled roads which go through the countryside. __61__ are good lane roads; others are uneven roads curving __62__ the country. These secondary routes may go up steep slopes, along hilly cliffs or down frightening hillsides to towns __63__ in deep valleys. Though these are less __64__ routes, longer and slower, they generally go to places __65__ the air is clean and the scenery is beautiful, and the driver may have a chance to get a fresh, clean view of the world.
51. A) Although B) But C) Since D) Because.
52. A) uneven B) bumpy C) rough D) smooth.
53. A) little B) much C) many D) few
54. A) terrible B) horrible C) tolerable D) enjoyable.
55. A) to B) into C) at D) by
56. A) merge B) connect C) combine D) mix
57. A) busy B) small C) large D) heavy
58. A) when B) where C) which D) that
59. A) walk B) go C) take D) fix
60. A) more B) less C) very D) extremely
61. A) All of these B) None of these C) All roads D) Some of these.
62. A) out of B) out C) through D) from
63. A) lying B) lie C) lies D) lay
64. A) direct B) indirect C) enjoyable D) beautiful.
65. A) these B) which C) that D) where
