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1. It is considered to be one of the most wonderful things that man has ever invented./It is considered as one of the most wonderful things that man has ever invented. (It is indeed one of the most...has ever invented)

2. We learn about people and events thousands of miles away. (Through this wonderful invention we learn about people and events thousands of miles away)

4. They prefer watching. (Students who cannot go to school....listening to the radio)

5. They are taught all their lessons at home through television. (Students who cannot go to school...at home through television)

6. Listening requires knowledge of many things, but what we see with our eyes explains that itself. (Listening requires knowledge...for a long time)