lǎo / shī / zài / hēi / bǎn / shàng / xiě / le / yī / gè / èr / cì / duō / xiàng / shì / ràng / wǒ / men / yīn / shì / fēn / jiě

老师在黑板上写了一个二次多项式让我们因式分解。

The teacher wrote a quadratic polynomial on the blackboard and asked us to factor it.