Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct option that best fits each numbered blank from 19 to 24.

By using computers people can do things (19) ________ than by using other means. Computers can do any calculations more rapidly than a skilled mathematician. (20) ________ a computer is programmed properly, it can work accurately. When we look back on the history of computer science, we can see the great (21) ________ between the old computers and the modern ones. The old computers work much slower than the modern ones. We can use the new generation of computers conveniently because of their small size and (22) ________ applied programs (23) ________  are widely used all over the world. We can get any sorts of information (24) ________ the Internet. These are the reasons why computers appear not only at offices but also at homes.