Complete it with the correct forms of the verbs given.Electricity is a basic part of nature and it is one of our most widely used forms of energy. Before electricity _____________ (discover) over 100 years ago, houses were lit with kerosene lamps, food ____________ (cool) in iceboxes, and rooms ____________ (warm) by wood-burning or coal-burning stoves.Electricity _______ (make) our lives easier. Right now, most of our electricity _______ (come) from burning fossil fuels (oil, natural gas, and coal). The problem is that fossil fuels will eventually run out. If we want to keep using our televisions, air conditioners, microwave ovens, and computers, we need to find another way to make electricity.