lì / shǐ / kè / shàng / lǎo / shī / jiè / shào / le / tiě / jiǎ / jiàn / zài / hǎi / zhàn / zhōng / de / zuò / yòng历史课上,老师介绍了铁甲舰在海战中的作用。In history class, the teacher explained the role of ironclads in naval warfare.