1、If we have a closed curve then the line integral for work is just zero.
如果給定一條封閉曲線，那么求所做功的線積分為零。

2、Well, you just take a closed curve in the plane.
只需在區(qū)域中取一條封閉曲線。

3、I need to be on a closed curve to do it.
我需要在一條封閉曲線上來做。

4、Stokes says if I have a closed curve in space, now I have to decide what kind of thing it bounds.
空間上存在一條閉合曲線，我需要看出它是什么的邊界。

5、Adds a closed curve to this path.
向此路徑添加一個閉合曲線。

closed curve翻譯