TEXT E
First read the question.
51. What is the author's main purpose in the passage?
A. to point out the importance of recent advances in archaeology.
B. to describe an archaeologist's education.
C. to explain how archaeology is a source of history.
D. to encourage more people to become archaeologist.
正确答案是

Now go though Text E quickly to answer question 51.
　
Archaeology is a source of history, not just a humble auxiliary discipline. Archaeological data are historical documents in their own right, not mere illustrations to written texts. Just as much as any other historian, an archaeologist studies and tries to reconstitute the process that has created the human world in which we live -- and us ourselves in so far as we are each creatures of our age and social environment. Archaeological data are all changed in the material world resulting from human action or, more succinctly, the fossilized results of human behavior. The sum total of these constitute what may be called the archaeological record. This record exhibits certain peculiarities and deficiencies the consequences of which produce a rather superficial contrast between archaeological history and the more familiar kind based upon written records.
　
Not all human behavior fossilizes. The words I utter and you hear as vibrations in the air are certainly human changes in the material world any may be of great historical significance. Yet they leave no sort of trace in the archaeological records unless they are captured by a Dictaphone or written down by a clerk. The movement of troops on the battlefield may "change the course of history", but this is equally ephemeral from the archaeologist's standpoint. What is perhaps worse is that most organic materials are perishable. Everything made of wood, hide, wool, linen, grass, hair, and similar materials will decay and vanish in dust in a few years or centuries, save under very exceptional conditions. In a relatively brief period the archaeological record is reduced to mere scraps of stone, bone, glass, metal, and earthenware. Still modern by a few lucky finds from peat bogs, deserts, and frozen soils, is able to fill up a good deal of the gap.
　
TEXT F
First read the questions.
52. The main subject of the passage is ____
A. famous mathematicians.
B. mathematical education.
C. tiling the plane.
D. irregular polygons.
正确答案是

Now go through TEXT F quickly and answer question 52.
　
Marjorie Rice was an unlike candidate for the role of mathematical innovator. She had no formal education in mathematics save a single course required for graduation from high school in 1931. Nonetheless, in 1975 she took up a problem that professional mathematicians had twice left for dead, and showed how much life was in it still.
　
The problem was tessellation, or tiling of the plane, which involves taking a single closed figure -- a triangle, for example, or a rectangle -- and kitting it together with copies of itself so that a plane is covered without any gaps or overlap. A region of this plane would look rather like a jigsaw puzzle whose pieces are all identical. Rice worked primarily with polygons, which consist only of straight lines. More specifically, she worked with convex polygons, in which the line joining any two points on the polygon lies entirely within the polygon itself or on one of its edges. (A five-pointed star, for example, does not qualify as a convex polygon.)
　
By the time Rice took up tiling, its basic properties had been established. Obviously, any square can tile the plane, as many kitchen floors have demonstrated. Equilateral triangles are also a fairly clear-cut case. There is one other regular polygon (a polygon whose angles, and sides, are equal) that can tile the plane: the hexagon. This fact was building their honeycombs.
　
And what of irregular polygons? As it turns out, any triangle or quadrilateral, no matter how devoid of regularity, will tile the plane. On the other hand, no convex polygon with more than six sides can do so, and the three classes of convex hexagons that can were uncovered by the end of the First World War. So the only real question lest by the time Marjorie Rice began her work was which convex pentagons tile the plane.