The following paragraph is about the importance of computers. Choose the correct verb tense.

Life without computers (1) seems/ has seems simply impossible now. Computers (2) affected/ have affected every aspect of our lives. Since the time they (3) were/ have been invented, computers (4) encouraged / have encouraged great technological progress in different fields. Along with computers, the Internet (5) aids/ has aided the developments in technology. However, many people argue that computers (6) killed/ have killed physical contact between people. For example, teenagers now (7) prefer/ have preferred chatting on the computer to meets face to face. Do you agree?