We are getting alarming reports of refugees being rounded up and shot.我们不断得到令人惊恐的报告，称难民被集中枪杀。New heavy industries were concentrated in tightly restricted areas.新的重工业被集中在严格限制的区域内。The visitors were herded into two large halls.游客们被集中在两个大厅里。They were herded together under guard.他们被集中在一处看管了起来。