Many people believe the glare（炫目的光）from snow causes snowblindness. Yet, with dark glasses or not, they find themselves suffering from headaches and watering eyes, and even snowblindness ,when exposed to several hours of“ snow light”.

　　The United States army has now determined that glare from snow does not cause snowblindness in troops in a snow -covered country. Rather ,a man’s eyes frequently find nothing to focus on （聚集） in a broad space of snow- covered without- grass land. So his gaze continually moves and jumps back and forth over the entire landscape in search of something to look at. Finding something, hour after hour, the eyes never stop searching and the eyeballs become tired and the eye muscles ache. Nature makes up for this discomfort by producing more and more fluid （流 体） which covers the eyeball. The fluid covers the eyeball in increasing quantity until it makes eyes difficult to see dearly, and the result is total, even though for a short time, snowblindness.

　　Experiments led the Army to a simple method of overcoming this problem. Scouts（侦察兵）ahead of the troops are trained to shake snow from evergreen bushes, creating a dotted line as they cross completely snow - covered landscape. Even the scouts themselves throw lightweight, dark - colored objects ahead on which they can focus too. The men following can then see something. Their gaze is arrested. Their eyes focus on a bush and having found something to see, stop searching the snow -blanketed landscape. By focusing their attention on one object at a time. the men can cross the snow without becoming hopelessly snowblind or lost. In this way the problem of crossing a continuous white land is overcome.

To prevent snowblindness caused by the strong light from snow, wearing glasses or not ________.

　　A. depends on whether the snow is white enough

　　B. makes no difference

　　C. makes much difference

　　D. depends on whether the snow is thick

When the eyes are tired, tears flow out ________.

　　A. to clear the vision

　　B. to make the eyes stop searching

　　C. to make the vision unclear

　　D. to produce more and more liquid

Snowblindness can be avoided ________.

　　A. by moving one’s gaze back and forth

　　B. by walking ahead and keeping looking around

　　C. by making up for the discomfort of one’s eyes

　　D. by providing the eyes with something to focus on

完形填空（共20小题；每小题1分，满分20分）
阅读下面短文，掌握其大意，然后从各题所给的四个选项（A、B、C、D）中，选出最佳选项。
On August 26, 1999, New York City experienced a terrible rainstorm. The rain caused the streets to _36_ and the subway system (地铁系统)almost came to a stop.
Unfortunately, this happened during the morning rush hour. Many people who were going to work were _ _37__ to go home. Some battled to _ _38__ a taxi or to get on a bus. Still others faced the _ _39_ bravely, walking miles to get to work..
I _ _40__ to be one of the people on the way to work that morning. I went from subway line to subway line only to find that most _ _41_ had stopped. After making my way _ _42  crowds of people, I finally found a subway line that was operating . __ 43_, there were so many people waiting to 44_ the subway that I could not even get down the stairs to the platform.(月台) So I took the train going in the _ _45 direction, and then turn back to the downtown train. Finally, after what seemed like an forever journey, the train _46_ my stop. Then I had to walk several blocks in the increasingly heavy rain. When I finally got to my office, I was _47__ through, discouraged and _48___.
My co-workers and I spent most of the day drying off. When it was 5:00 pm，I was ready to go home. I was about to turn off my computer __49___ I received an email from Garth, my Director:
I would like to thank all of you who made the effort and __50__ reported to work. It is always reassuring(令人欣慰), at times like these, when employees so clearly __51___ their devotion(（忠心）  to their jobs. Thank you.
Garth’s email was short, but I learned more from that __52__ message than I ever did from a textbook. The e-mail taught me that a few words of __53____ can make a big difference. The rainstorm and the traffic __54__ had made me tired and upset. But Garth’s words immediately_55__ me and put a smile back on my face.
36. A. break            B. flood              C. sink                  D. run
37. A. forced           B. refused              C. ordered             D. gathered
38. A. order            B. pay                   C. call                   D. search
39. A. climate        　 B. weather             C. storm                D. snow
40. A. used              B. promised           C. seemed             D. happened
41. A. practice          B. traffic               C. process             D. service
42. A. to               　B. through             C. over                  D. for
43. A. Unfortunately      B. Luckily      C. Interestingly      D. Satisfyingly
44. A. check              B. carry          C. find             D. board
45. A. only              B. similar         C. same             D. opposite
46. A. paused            B. crossed         C. reached          D. parked
47. A. wet                B. weak       C. sick             D. hurt
48. A. interested        B. tired          C. surprised       D. puzzled
49. A. while             B. when          C. where          D. after
50. A. hardly            B. happily        C. firstly         D. finally
51. A. show              B. carry          C. take          D. fetch
52. A. basic           B. attractive       C. brief               D. original
53. A. promise          B. appreciation       C. advice             D. position
54. A. troubles         B. signals       C. rules         D. signs
55. A. corrected         B. supported          C. surprised           D. delighted