1) Who helped the professor to perform the experiment?
2) Did the young assistant help the professor to perform the experiment?
3) Whom did the young assistant help?
4) Did the young assistant help the professor to perform the experiment or describe it?
5) The young assistant helped the professor to perform the experiment, didn't he?
6) What did the young assistant do?
1) Who helped the professor to perform the experiment?
2) Did the young assistant help the professor to perform the experiment?
3) Whom did the young assistant help?
4) Did the young assistant help the professor to perform the experiment or describe it?
5) The young assistant helped the professor to perform the experiment, didn't he?
6) What did the young assistant do?