错.应为Tom is the only one of the workers who was praised at the meeting.意思是Tom是会议上唯一被表扬的员工.the only one of 是“唯一一个”.
也可以是Tom is only one of the workers who were praised at the meeting.这是说Tom是会议上被表扬的员工中的一个.这里only是“仅仅、只是”,one of the workers是“员工中的一个”.
有the和没the差别很大.