Виберіть правильну форму Present Perfect.

​John (NOT GO) to the supermarket. He’s still here.
has not go
have not gone
has not gone
has not went​

The future of cyberspace.Over the past thirty years, the Internet has grown dramatically. In 1983, only 200 computers connected to the Internet; Now there are about 50 million of them, and this growth will clearly continue. One of the concerns is the work of cybercriminals. In the future, cyber-terrorists can attack computers in the world, cause chaos. Now users can buy book offers. "In the next few years," says Angela Rossetto of Cyberia magazine, "it's obvious that we'll see an explosion of purchases on the Internet."She also believes that in the future we will get entertainment from the web and that television is likely to disappear. The postal service may disappear as the use of e-mail grows.Some experts see our future in virtual reality - using computers with sounds and images that make you feel in a real situation.

1. Quite a large number of definitions (are given) to statistics as a science.
2. The war (has brought) major changes in the programme of statistical work and the methods of observation and processing.
3. All progressive knowledge in the modern world (is tending) to precision.
4. At present many countries (have declared) themselves republics, some of them (have become) independent and encourage the use of local languages.
5. They (had been working) there for more than three hours when it (happened).
6. Nowadays some difficult economic problems (are being solved) on the basis of statistical data.
7. A theory (is known) to be tested by practice.