You have to go into politics    you want to change the world.

A．if      B．so     C．although   D．unless

完形填空 阅读下面的短文，掌握其大意，然后从各题所给的A、B、C和D选项中，选出最佳选项。（每小题2分，共30分）
Computers have done us a lot since they turned up. In the future they will play a more important part in many __16__, such as education, transport, personal lives, scientific research and so on. Nowadays computers are being used in ___17__ and industry and can help the farmers to __18__ the conditions of the plants.
More and more computers will come into our daily life with the __19__ of science and technology. If you want to change money or pay your electricity bills, you won’t have to go to the __20__. A computer and a telephone will help you. It can also help you to do the housework and it can even __21___ human voices and carry out the instructions. It is __22__ that the majority of the labor force will work at home. People will be able to use the videophone for conferences. This can help us to save a lot of energy and ___23__. It is said that trains in Japan will have no __24___, because they’ll be well __25___ by computers, which can also tell the best ___26__ between trains.
Computers programs for __27__ whole texts are already well developed. You can ___28__ the name of a certain subject and a __29__ list of book titles will __30__ on your screen. You may choose whichever you want.