1. A. compulsory

B. technology

C. academic

D. eliminate

2. A. exploration

B. attractive

C. conventional

D. impatient

3. A. responsible

B. apprehension

C. preferential

D. understanding

4. A. responsibility

B. trigonometry

C. conversation

D. documentary

5. A. doubtful

B. solidify

C. politics

D. stimulate

6. A. brotherhood

B. vertical

C. opponent

D. penalty

7. A. economics

B. sociology

C. mathematics

D. philosophy

8. A. climate

B. attractive

C. graduate

D. company

9. A. satisfy

B. sacrifice

C. apology

D. richness

10. A. activity

B. allergic

C. volunteer

D. employer

11. A. automatic

B. reasonable

C. mathematics

D. preservation

12. A. dangerous

B. successful

C. physical

D. gravity

13. A. specific

B. coincide

C. inventive

D. regardless

14. A. habitable

B. famously

C. geneticist

D. communist

15. A. abnormal

B. initial

C. innocent

D. impatien