lǎo / shī / zài / shí / yàn / kè / shàng / jiǎng / jiě / le / gé / lán / shì / rǎn / sè / de / jī / běn / bù / zhòu老师在实验课上讲解了革兰氏染色的基本步骤。The teacher explained the basic steps of Gram staining in the lab class.