The Mayo Clinic says you may feel a tension headache as tightness in the skin around your eyes.

VOA: special.2010.03.30

I'm going to ask everybody in this half of the class please either turn your head or shut your eyes.

请左边的同学转过头去,或是闭上双眼。

耶鲁公开课 - 心理学导论课程节选

Harmony is indeed invisible in sense Number 1, you cannot see it with your eyes, but for all that, it can be destroyed.

和声用无形的第一种解读方式理解，确实是无形的，你看不见它，但是它可以毁灭。

耶鲁公开课 - 死亡课程节选

In theory. Then close your eyes.

VOA: standard.other

In fact the number of photons headed to your your eyes from those 2 tiles is exactly the same, physically that is the same.

实际上这两张瓷片,投射进你眼睛的光量子是一样的，从物理学的角度上说是完全相同的。

斯坦福公开课 - 7个颠覆你思想的演讲课程节选