Question

3 Choose the correct answers. The light bulb What would we do without electric lights? In the 1800s, light bulbs 1___ by different people, but none of them were good enough to sell until the right material to go inside the bulb 2___ Thomas Edison. Since then, electric lights 3___ around the world by billions of people. The original design 4___ much, although more energy-efficient light bulbs 5___ now in many parts of the world. However, in some countries, people can’t afford to use electricity. This fact encouraged U.S. teenager Ann Makosinski to invent a new kind of light. This light 6___ by electricity. It uses body heat instead. But 7___ replaced by this new invention in the future? Probably not, but light 8___ and so this invention could definitely become popular in many parts of the world. 1 a are developed 2 a were discovered by 3 a have used 4 a isn’t changed 5 a will be bought 6 a isn’t powered b developed b was discovered b have been used b won’t change b is bought b wasn’t powered c weredeve​

Answer 1

1. were developed

2. was discovered by

3. have been used

4. hasn't been changed

5. are bought

6. isn't powered

7. will the light bulb be

8. will always be needed

:)