Lì / shǐ / kè / shàng / lǎo / shī / jiè / shào / le / Qí / gé / fēi / fáng / xiàn / de / zhàn / lüè / yì / yì

历史课上，老师介绍了齐格菲防线的战略意义。

In history class, the teacher explained the strategic significance of the Siegfried Line.