【简答题】A group of researchers have discovered a new medical herb,which they have ______ a large number of patients and found to have great healing power. 一组调查人员发现了一种新的草药,他们把它使用在大量的病人身上,发现有很好的疗效。
【单选题】The age of the general practitioner is over. More and more graduates of medical schools tend to ______, that is, to concentrate on limited areas of their profession.