At the international conference, the scientist gave a report (base) ______ on his recent experiments.
                    举一反三
- At the international conference, the famous scientist gave an excellent report ________ on his recent experiment.
 - At the international conference, the famous scientist gave an excellent report ________ on his recent experiment. A: basing B: based C: to be based D: to base
 - At the international meeting, the famous expert gave an excellent speech _____ on his recent research. A: asing B: . based C: to be based D: to base
 - _______ several times, the young scientist still kept on making his experiments.
 - They are busy doing ______________(scientist) experiments.
 
