perspicacious

这位教授对学生的问题总能给出敏锐而深刻的见解。

The professor always provides ___perspicacious insights into students' questions.

老师敏锐地发现那个学生其实很聪明，只是缺乏自信。

The teacher's ___perspicacious insight revealed that the student was actually very smart, just lacking confidence.