yī shēng / yòng / chuí zi / qiāo jī / xī gài / xiǎo tuǐ / huì / lì kè / zuò chū / fǎn shè dòng zuò

医生用锤子敲击膝盖，小腿会立刻做出反射动作。

The doctor tapped the knee with a hammer, and the lower leg immediately made a reflex action.