The deformations of the element in the middlesurface of the shell and its rotation about all axes are considered in the derivation of these equations.
在推导过程中，考虑了壳体微元在中面内的变形和绕各个轴的转动。
2
In the late Middle Ages, it was customary to scrape away the surface of the parchment with an abrasive, which completely wiped out any writing that was there.
在中世纪后期，人们习惯用磨料刮去羊皮纸的表面，把纸上的所有文字都擦得干干净净。
3
Say when you're at the front of C prime, your thumb points to the right, your index points up because that's where the surface is, and then your middle finger will point out.