Tiān / wén / xué / kè / shàng / lǎo / shī / jiè / shào / le / tài / yáng / xì / wài / wéi / de / kù / pò / dài天文学课上,老师介绍了太阳系外围的库珀带。In astronomy class, the teacher introduced the Kuiper belt on the outskirts of the Solar System.