From the earlier time it was well ___1___to the Peruvians that when a cut ___2____made in the thick skin of a ___3____tree, a white liquid like milk came ___4___. From this fluid (流动的) a sticky ___5_____of rubber might be made. This rubber is ___6____and wax-like when warm so that it is ___7_____to give any form.
The Peruvians ___8____the discovery that it is very good for ___9____out water. Then in the early ___10____of the century they made overshoes to ___11___their feet dry. Then a certain Mr Mackintosh ___12_____coats of cloth which were ___13____with rubber. Today Mackintosh raincoats are still ___14_____after him.
But these first rubber shoes ___15______raincoats were unpleasantly soft and sticky in ___16___. They were also stiff and very ___17____in winter. They were like wax(蜡) although they ___18____a bit stronger.
But the rubber ___19___use today has been improved. It is ___20____sticky but soft and elastic(弹性的) and strong enough for any season.
1. A. talked B. heard C. seen D. known
2. A. has B. was C. may D. will
3. A. rubber B. apple C. orange D. oak
4. A. from B. through C. out D. up
5. A. raincoat B. shoes C. border D. mass
6. A. hard B. fast C. stubborn D. soft
7. A. important B. impossible C. possible D. uncertain
8. A. made B. found C. wrote D. neglected
9. A. finding B. keeping C. making D. pouring
10. A. kind B. part C. sort D. halves
11. A. clean B. clear C. keep D. prevent
12. A. made B. found C. appeared D. gave
13. A. full B. like C. lined D. applied
14. A. looked B. named C. made D. searched
15. A. or B. and C. with D. but
16. A. today B. summer C. winter D. rain
17. A. soft B. sticky C. elastic D. cold
18. A. felt B. made C. needed D. produced
19. A. Mr Mackintosh B. the Peruvians C. we D. is
20. A. also B. always C. neither D. not
缺失，拟行可摘局部义齿修复，末端基牙采用RPI卡环