The angle θA will change

θA 的角度数会发生变化
but the angle with the new x axis won't be the same.

它和新 x 轴的夹角要改变
The angle with the new y axis won't be the same.

与新 y 轴的夹角也会不同
Likewise for B,

向量 B 同理
but the angle between the vectors,

但两个向量间夹角不变
it's an invariant property, something intrinsic to the two vectors,

这是两个向量间固有不变的量
doesn't change, so the dot product is an invariant.

所以点乘积是个定值
This is a very important notion.

这个概念很重要
When you learn relativity,

当你们学习相对论时
you will find you have one observer saying something,

你会发现某个观察者看到这样
another observer saying something.

另一个观察者看到那样
They will disagree on a lot of things,

他们的很多看法都会不同