n.四音音阶；完全四度；四弦琴
Two artists in December when in new York Bulukelin conducted a concert, with tetrachord the performance wraps around the song of head person. 两个艺术家12月的时候在纽约布鲁克林举办了一场音乐会，用四弦琴表演披头士的歌。
Finally, buffett bought the tetrachord of rare the name of a river in Shaanxi and Henan provinces of 17 transparent red. 最后，巴菲特买了17把透明红色的希洛四弦琴。
What she sang was a little bit difference with what Hai Xi Xi sang yesterday, the undulate of melody was little, end sound was close to tetrachord and hexachord. 她今天唱的和海喜喜昨天唱的又有所不同。旋律起伏较小，尾部结束音向上作纯四度和大六度滑近。
' " memory says Weierhaimu, "I say is, next she asks, ' is world head then rich do not play tetrachord? ’”威尔海姆回忆说，“我说是，然后她问，‘那世界首富就不弹四弦琴了吗？’”
