（ C ）
　　I wonder why American towns looks so much alike that I sometimes mix them up in my memory. The standard influence（影响）of mass
　　production whose agents（代理商）are the travelling
　　salesman， the mail-order house， the five-and-ten cent stores， the chain stores， the movies can hardly explain it. If you stay
　　two days in Bologna and in Ferrare， or in Arles and in Avignon， you will never mix them up in all your life. But it may well
　　happen that after you spend two days in St.Louis and in Kansas City the appearances of these two cities soon mix up. I think
　　the reason for this is that these towns have not yet had time enough to develop their own characters. Similarly， children are
　　much less different from each other than grown people.
　　44. Which two of the following towns look so much alike？
　　A. Bologna and Ferrare B. Arles and Avignon
　　C. St. Louis and Kansas City D. Bologna and St. Louis
　　45. In line 4 the word “it” refers to ____________.
　　A. standard of towns B. similarity of towns C. people’s memory D. mass production
　　46. American towns look very much alike because of ____________.
　　A. the standard influence of mass production B. their different appearances
　　C. not being fully developed D. having everything in common
　　（ D ）
　　Millions of stars are travelling about in space. A few form groups which journey together， but most of them travel alone.
　　And they travel through a universe so large that one star seldom comes near to another. For the most part each star makes
　　its journey in complete loneliness， like a ship on an empty ocean. The ship will be well over a million miles from its
　　nearest neighbor. From this it is easy to understand why a star seldom finds another anywhere neat it.
　　We believe， however， that some two thousand million years ago， another star wandering（漫游） through space， happened to come
　　near our sun， Just as the sun and the moon raise tides（潮汐）on the earth， so this star must have raised tides on the
　　surface of the sun .But they were very different from the small tides that are raised in our oceans； a large tidal wave
　　must have travelled over the surface of the sun， at last forming a mountain so high that we cannot imagine it. As the cause
　　of the disturbance（动荡） came nearer， so the mountain rose higher and higher. And before the star began to move away again，
　　its tidal pull had become so powerful that this mountain was torn to pieces and threw off small parts of itself into space.
　　These small pieces have been going round the sun ever since. They are the planets（行星）。
　　47. Millions of stars are _______________.
　　A. following a regular path in space B. moving about without a fixed course
　　C. seldom wandering about in the universe D. always travelling together
　　48. Some two thousand million years ago， the mountain on the sun was raised probably because
　　__________.
　　A. a large tidal wave of a star travelled over the surface of the sun
　　B. another star happened to come near the sun
　　C. the sun and the moon raised the tides on the earth
　　D. the star moved away from the sun
　　49. The article suggests that _____________ .
　　A. our earth exists before the sun B. how space formed
　　C. no one knows where the earth comes from
　　D. our earth used to be a high mountain on the sun
　　50. The expression “the cause of the disturbance” refers to _________.
　　A. the large tidal wave B. the powerful tidal pull
　　C. the star coming near the sun D. one of the sun’s planets
　　51. In this article， the writer mainly wants to tell the readers __________.
　　A. that the universe is so large that we cannot imagine it
　　B. how the high mountains were formed on the sun
　　C. why the tides over the surface of the sun were so powerful
　　D. where the planets in the universe came from