1. Don't use ________ chemicals. They're harmful to our health. (to poison/ poison/ poisonous) 2. Water pollution has ________ the river. Nobody swims there. (contaminate/ contaminated/ contamination) 3. Water pollution causes the _______ of a lot of fish. (death/ to die/ dead) 4. Water pollution causes a lot of fish to ________. (death/ die/ dead) 5. The acid rain has caused great __________ to the environment. (to damage/ damaged/ damage) 6. The polluted air __________ our health badly. (to damage/ damages/ damage) 7. The serious _________ has left the river with very few fish. (contaminate/ contaminated/ contamination)