1. We are wasting too few water and power. (The correct answer is B. "few" should be replaced with "much" to indicate a larger quantity of water and power being wasted.)

2. The world need more food because there are more people. (The correct answer is A. "need" should be replaced with "needs" to match the subject "world" which is singular.)

3. Not burn too much coal, oil and gas. (The correct answer is A. "Not" should be replaced with "Do not" to form a complete sentence.)

4. Why are we doing to our environment? (The correct answer is C. "doing" should be replaced with "doing harm" to indicate the negative impact on the environment.)