So Jim takes one of the volunteer participants—call her Sarah.

于是吉姆带了一位志愿者参加——叫她莎拉。

A total of 21 volunteers—participants in the competition, judges and members of the local symphony orchestra—were asked to put the instruments through their paces.

总共有21名志愿者—分别来竞赛的选手，评委和当地交响乐团的乐手—来检验这些小提琴的优劣。