Lì / shǐ / kè / shàng / lǎo / shī / jiè / shào / le / Pǔ / shì / sì / cì / qián / wǎng / Zhōng / yà / tàn / xiǎn / de / jīng / lì

历史课上，老师介绍了普氏四次前往中亚探险的经历。

In history class, the teacher described Przevalski's four expeditions to Central Asia.