ইংরেজি ২য় পত্র প্রশ্ন

The second half of the twentieth century saw more changes than the previous two hundred years. There were many remarkable advances in medicine that helped to increase our average life expectancy way beyond that of our ancestors. Incredible innovations such as television changed the way we spend our leisure hours. Perhaps the most important breakthrough, however, has been the microchip. Nobody could have imagined, when it was first invented, that within a matter of years, this tiny piece of silicon would be found in almost every household object from the kettle to the video recorder. And nobody could have predicted the sudden proliferation of computers that would completely change our lives, allowing us to access information from the other side of the world via the internet/www or send messages around the world by e-mail at the touch of a button. Meanwhile, research into other aspects of information technology is making it easier and cheaper for us to talk to friends and relations around the world.*'Life expectancy' means: