This one is a line integral. So, you use the method to explain here, namely, you express x and y in terms of a single variable.

这一个是线积分，可以用这里的办法来做，也就是用一个变量来表示出来。

youdao

First, you design services that are common to all members of the product line, using the method described in the design section for single systems.

首先，你要使用针对单一系统的设计部分中描述的方法，设计产品线的所有成员共有的服务。

youdao

First, you identify candidate services that are common to all members of the product line, using the method described in the analysis section for single systems.

首先，你要使用针对单一系统的分析部分中描述的方法，确定产品线的所有成员共有的候选服务。

youdao

Although the single-line method may be faster, Mr. Hammack says customers generally prefer to "jockey for position" in separate lines.

WSJ: Find the Best Checkout Line