think, consider, ponder; final particle 思：思考

思考[sī kǎo] think

思想[sī xiǎng] thought

思乡[sī xiāng] nostalgia

思念[sī niàn] miss

Qín yú sī kǎo cái néng fā xiàn wèn tí。

勤 于思 考 才 能 发 现 问 题。

You can only find the problem through diligent thinking.