5. He has published his first article only two years ago and now he is a well known specialist in this field

6. My brother cannot decide yet what faculty to choose

7. You ever had meet this man? No, I never had meet him

8. You have translate this text already? Yes I have translate it

9. When the conference on ultrahard fibers took place? It took place last month

10. You had to surprise me yesterday. I didn't expect you to come

11. Marie Curie has discovered a new chemical element which was called "polonium"

12. We have to repeat the experiment several times this week. The results are always the same

Если не правильно, прости потому что я не понял, тут у тебя должна быть одна грамматика, а она тут не определена