I.

1. B 2. A 3. B 4. C 5. A
II. 6. Natural 7. harmful 8. contaminated 9. polluted
10. unable 11. environmental
III. 12. to 13. into 14. to 15. away 16. with
IV. 17. If people dump wastes and poisonous chemicals into water, tiny animals will eat
pollutants in polluted water.
18. If tiny animals eat pollutants in polluted water, fish and shellfish eating tiny animals will
contain poison in their bodies.
19. If fish and shellfish eating tiny animals contain poison in their bodies, people who eat
these fish will get some diseases.
20. If people who eat these fish get some diseases, they will have to go to hospital.
21. If they have to go to hospital, their family members will take care of them.
V. 22. results → results in 23. make → cause