placing reflex

例句：

1. 1.The scientist placed the sample in a test tube and observed its reflex.
   科学家将样本放入试管中并观察其反射。
2. 2.The teacher noticed that the student had a good reflex for solving problems quickly.
   老师注意到学生在解决问题时有很好的反射能力。
3. 3.The researcher conducted an experiment to study the reflex of light on water droplets.
   研究者进行了实验以研究光线对水珠的反射。