With some adjustments to the engine, it is possible to (swap) substitute vegetable oil for gasoline in some vehicles. With land burning throughout the western United States, more firefighters were brought in to (fight) combat the huge wildfires. These days, farmers use highly sophisticated machines to (pick) harvest their crops. Before computers, librarians had to (organize, list) catalog all books by hand. The heat was (too much) excessive . People were warned to stay indoors. There is general (agreement) consensus within the scientific community that global warming exists, but scientists hold different opinions about how to address it. After he graduated from university, he managed to pay off all his (money owed) debt within 3 years. The city decided to (try to solve) tackle the housing problem by first holding public meetings in order to listen to the residents' ideas for improvement.  When a threatened species of bird was discovered in the forest, all tree cutting was (stopped) halted . Wind and solar power are examples of (replaceable) renewable energy sources.