lǎo / shī / xiān / huí / dá / le / xué / shēng / tí / chū / de / jī / chǔ / wèn / tí / zài / jiǎng / jiě / gèng / fù / zá / de / nèi / róng

老师先回答了学生提出的基础问题，再讲解更复杂的内容。

The teacher first answered the basic questions raised by the students and then explained more complex material.