xiào / zhǎng / kāi / chú / dài / tóu / nào / shì / de / xué / shēng / shì / wèi / le / shā / yī / jǐng / bǎi

校长开除带头闹事的学生，是为了杀一儆百。

The principal expelled the student who led the disturbance as a warning to the others.