四级冲刺练习阅读134

　　11 in these rings relates to the physical conditions which the tree experiences. Thus, trees grown in a 12 area and time each develop a pattern or configuration of their rings.

　　This 13 was of little significance until Andrew E. Douglas began to study tree rings in Arizona in 1900. Using a technique called cross dating, he was able to employ tree rings to the study of archaeological sites and date the ruins with 14 . Some were as old as 6700 B. C. ! This study of tree rings is called dendrochronology.

　　In time the cross dating was 15 by a carbon 14 process. This approach measured the amount of carbon 14 radiating from a piece of wood and 16 to determine the age of that wood. Further use of the carbon 14 technique has shown that the radiation process is more complex and less 17 than had been at first thought.

　　The most 18 aspect of tree ring research is now called dendroclimatology. This 19 of the reconstruction of climates and climatic cycles and events from the evidence found in the tree rings.

　　Recently the attack on illiteracy has been 13 up. A world plan has been drawn up by a committee of UNESCO experts in Paris, as part of the UNESCO Nations Development Decade, and an international conference on the 14 has also been held. UNESCO stresses that functional literacy is the aim. People must learn the 15 skills of responsible 16 : the ability to read notices, newspapers, timetables, letters, pricelists, to keep simple records and accounts, to 17 out the significance of the information gathered, and to fill in forms.

　　The 18 areas of illiteracy are in Asia, Africa, and Central and South America. In Africa there are at least one hundred million illiterates, 19 eighty to eighty-five per cent of the 20 population. In Europe the figure is about twenty-four million, most of them in Southern Europe, with Spain, Italy, Portugal, and Yugoslavia heading the list .

　　A. basic B. citizenship C. stepped D. some

　　E. major F. barely G. sort H. membership

　　I. superior J. entire K. scarcely L. constituting

　　M. total N. subject O. comprising

　　II. D 12. F 13. C 14. N 15. A 16. B 17. G 18. E 19. O 20. M

　　From this it is hoped that a 20 of drought cycles can be determined in the American Southwest. Such information will be of great help in determining the life and ecology of that region of the United States.

　　A. thus B. model C. variation D. concept

　　E. accuracy F. exciting G. consists H. given

　　I. proposition J. composes K. further L. pattern

　　M. supplemented N. reliable O. excellent

　　II. C 12. H 13. D 14. E 15. M 16. A 17. N 18. F 19. G 20. L