1. today/ water power/ mostly/ used/ generate electricity/.
→Today water power is mostly used to generate electricity
2. energy/ from/ sun/ be/ clean/ cheap/ safe/.
→The energy from the sun is clean, cheap and safe
3. earth’s/ fossil/ fuels/ running/ out/.
→Earth's fossil fuels are running out
4. what/ happen/ when/ there/ no energy/ earth/?
→What will happen when there is no energy on Earth ?
5. we/ looking/ for/ alternative/ sources/ energy/.
→We're looking for the alternative sources of energy