На дне и крышке консервных банок выштампованы концентрические круги (гофры). Какое они имеют значение?

1. He is said TO HAVE been promoted.
2. The students were told not TO use their notes at the exam.
3. It was reported that the sides HAD reached the decision on students' exchange program.
4. It should HAVE been recognized that all jobs are necessary for the society.
5. The bill 'On Higher Education' has been drawn BY the President.
6. Students are expected to digest knowledge from a wide variety of sources.
7. The word 'stupid' was in my report but it was not referrING to you.
8. When did you discover that the money had disappeared?
9. The football fans were observed BY the police.
10. By whoM WAS the telephone answered?