and Mexican officials. Every day, thousands of people on foot and in vehicles go back and forth across the border here, and millions of dollars worth of products cross the line in trucks and railroad cars.

VOA: standard.2009.04.30

So, let's listen to this bit of klezmer music go back and forth between minor and major.

让我们感受下这段犹太音乐,它在小调和大调之间转换

耶鲁公开课 - 聆听音乐课程节选