Pair work: Work with your partner to complete the following dialogues, using the words and phrases in brackets. Make changes or additions where necessary.1. A: Why will oil cease to be the No. 1 problem of our time?B: The dawn of a new energy era is ____ . Oil prices are ____ because solar power is becomingcheaper. Besides, improvements in energy _____, while helping to create a clean _____ , are reducing waste and the demand for oil. (go down, environment, around the corner, efficiency)2. A: Why isn't it easy to solve the water problem?B: Because water is far _____ than energy. No other _____ water, so it is impossible to find _____ it. Besides, water demand is rising, but water supply is fluctuating as a result of climate change. (resource, complicated, alternative, replace)3. A: Why is it important for us to conserve water?B: Water is going to be the most contentious _____ of the 21st century. It will trigger geopolitical _____ . That's why water _____ is not only ____ our economy but also a task of _____ importance. (conservation, in the interest of, conflict, strategic, resource)