Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23.

Electricity is one of the most important inventions ever. It is the thing that powers the Earth. If there was no (19) _________, we’d be back in the dark ages. Few people stop and think just how amazing electricity is. With the flick of a switch, you can power almost anything. Think (20) _________ what would happen if there was no electricity. We’d have no TV, no computers, no traffic signals. It would be like going back to living in caves. There are a few negative points about electricity, of course. Number one, it’s dangerous. Thousands of people (21) _________ every year from electrocuting themselves or in electrical fires. (22) _________ number two, it isn’t good for the (23) _________. Most electricity comes from burning coal and that creates greenhouse gasses.

Electricity is one of the most important inventions ever. It is the thing that powers the Earth. If there was no (19) _________, we’d be back in the dark ages