1.They asked us to stay a little longer. - We were asked to stay a little longer. 2. People have made great progress in physics. - The great progress was made by people. 3. They are discussing the possibility of new negotiations. - The possibility of new negotiations was dicsussed by them. 4. People use coal for making artificial materials. - Coal was used by people for making artificial materials. 5. They elected him President of the Club last year. - He was elected President of the Club by them last year.
2. People have made great progress in physics. - The great progress was made by people.
3. They are discussing the possibility of new negotiations. - The possibility of new negotiations was dicsussed by them.
4. People use coal for making artificial materials. - Coal was used by people for making artificial materials.
5. They elected him President of the Club last year. - He was elected President of the Club by them last year.