9 A use B usage C activity D construction
10 A estimated B taught C called D recommended
11 A innovative B necessary C accurate D strict
12 A occasions B times C cases D examples
13 A invented B expanded C modified D developed
14 A That B This C Such D So
15 A complex B basic C serious D favorable
参考答案：
1. C 2. C 3. B 4. B 5. A
6. B 7. D 8. C 9. A 10. A
11. C 12. C 13. D 14. C 15. B
