Lǎoshī duì měi gè xuéshēng de qíngkuàng liǎorúzhǐzhǎng.
The teacher knows each student's situation thoroughly.
Tips
memory
Look at your own palm — you know every line, every crease. That's how well someone knows the subject: 了 (clear) 如 (as) 指掌 (finger-palm).
history
From the ancient text 《论语》. Confucius said that whoever understands the imperial sacrifice would govern the world as easily as looking at their own palm.
