lì / shǐ / kè / shàng / lǎo / shī / xiáng / xì / jiǎng / le / sì / yī / èr / shì / jiàn / de / jīng / guò

历史课上，老师详细讲了四一二事件的经过。

In history class, the teacher explained in detail the course of the April 12th Incident.