and I'm trying to move them across each other

试图使两块平板发生相对位移
so that's a shear force.

因此就产生了剪切力
The deformation is not a deformation like it increases in length,

形变不再是像先前长度增加的那种形变
the deformation is that the wall on top moves and it moves continuously.

这种形变是面上的位移持续性的位移
Imagine if I start to apply-- I have this setup here,

想象一下如果我有套这样的装置
the desktop is on top of the layer fluid, on top of the desktop below,

一层液体其上下各有一个桌面
and I somehow apply a constant force to that top plate,

我对上面那块板的某处施以一个持续的力
that top desktop, it's going to continue to

上面的板就会一直移动
move as long as I apply a constant force it'll move,

只要我施加的力还在它就一直移动
it'll move, it'll move, eventually I'd fall off the desk here.

移动移动直到从桌子上滑落
What's created is not a strain, what's created is a velocity.

造成这一现象的不是应力而是速度
The top plate is going to move,

如果我对顶板施加一个持续性的力