1. I never changed the motherboard
2. He bought a new mobile phone this week and all the time playing with him
3. We have not yet studied this device
4. Last Tuesday we listened to a lecture on the computer's memory
5. Why did not you answer the question of the teacher in the previous lesson?
6. I have not seen Mary this week
7. You have studied computer input device?
8. I just replaced the hard drive, is now working on the computer a pleasure
9. I have just discussed the purchase of a new computer with parents
10. I did not repeat this poem last week
11. The teacher spoke about the output device, and now I'm writing a paper on the different types of printers
12. I just installed an anti-virus program on your computer
13. You have already viewed the e-mail? I sent you a letter yesterday
14. Last Wednesday, the lesson we listened to a lecture on new applications
15. I bought a new i-background last week
16. When you're finished reading this book?
17. He did not like the lecture, he did not write for a teacher
18. You have finished the discussion? Let's continue with the lesson.
19. Did you see Anna today?
20. The teacher has not come yet, we are waiting for him.