OK, so there's the line integral.

这就是线积分了。

We have a line integral along a curve.

对于沿曲线的线积分。

This side here is a usual line integral.

这边是普通的线积分。

A line integral for flux just becomes this.

求通量的线积分就变成这样了。

And we will evaluate the line integral for work.

为了求做功，我们要计算线积分。