II. Supply the correct form of the words in bracket. 1. Unfortunately. Biogas isn’t totally ___________ to people. (harm) 2. Nuclear power is ____________, but it is very dangerous. (plenty) 3. Disposable batteries are _____________ the environment. (pollute) 4. Scientists are finding an _____________ source to replace gasoline. (limit) 5. Will ______________ energy sources be banned from using in the future? (new) 6. We should think ____________ how to protect our environment. (positive) 7. _____________ gas is going to run out someday. (nature) 8. It is predicted that there will be a serious _____________ of energy in the future. (short) 9. Renewable energy is an __________ source of energy. It is unlimited. (exhaust) 10. One of the ______________ of wind power is that it is unavailable. (advantage)