四六级考试

根据网考网考试中心的统计分析，以下试题在2015-11-23日四六级考试六级习题练习中，答错率较高，为：82%
【单选题】Icebergs are among nature's most spectacular creations, and yet most people have never seen one. A vague air of mystery envelops them. They come into being-somewhere-in faraway, line frigid waters, amid thunderous noise and splashing turbulence, which in most cases no one hears or sees. They exist only a short time and then slowly away just as unnoticed. 
Objects of sheerest beauty, they have been called. Appearing in an endless variety of shapes, they may be dazzlingly white, or they may be glassy blue, green, or purple, tinted faintly or in darker hues. They are graceful, stately, inspiring-in calm, sunlit seas. 
But they are also called frightening and dangerous, and that they are in the night, in the fog, and in storms. Even in clear weather one is wise to stay at a safe distance away from them. Most of their bilk is hidden below the visible top. Also, they may roll over unexpectedly, churning the waters around them. 
Icebergs are parts of glaciers that break off, drift into the water, float about a while, and finally melt. Iceberg afloat today are made of anowflakes that have fallen over long ages of time. They embody snows that drifted down hundreds, or many thousands, or in some cases maybe a million year ago. The snows fell in polar regions and on cold mountains, where they melted only a little or not at all, and so collected to great depths over the years and centuries. 
As each year's snow accumulation lay on the surface, evaporation and melting caused the snowflakes slowly fell on the top of the old, it too turned to icy grains. So blankets of snow and ice grains mounted layer upon layer and were of such great thickness that the weight of the upper layers compressed the lower ones. With time and pressure from above, the many small ice grains joined and changed to larger crystals, and eventually the deeper crystals merged into a solid mass of ice.
46. Which of the following is the best title for the passage?
A. The Name and Origin of Icebergs
B. The Size and Shape of Icebergs
C. The Dangers of icebergs
D. The melting of Icebergs
47. The author states that iceberg are rarely seen because they are _____.
A. broken by waves soon after they are found
B. hidden beneath the mountains
C. located in remote regions of the work
D. surrounded by fog
48. In Para 5, line 6 the expression "from above" refer to _______.
A. sunlit seas
B. polar regions
C. weight of mountains 
D. layers of ice and snow
49. According to the passage, icebergs are dangerous because they _____.
A. usually melt quickly
B. can turn over suddenly
C. may create immense snowdrifts
D. can cause unexpected avalanches
50. "Dazzlingly" in Para 2 line 2 probably means _____.
A. brilliant
B. faint
C. beautify
D. sick