zhè / gè / hái / zi / de / xiǎng / fǎ / biàn / huà / mò / cè / lǎo / shī / hěn / nán / tí / qián / pàn / duàn / tā / de / fǎn / yìng

这个孩子的想法变化莫测，老师很难提前判断他的反应。

This child's thoughts are unpredictable, making it difficult for the teacher to anticipate his reactions.