技巧4：选择第一个具有某名称的元素。

Tip 4: Selecting the first element with a certain name.

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接下来，考虑如何选择第一个文档的名称。

Next, consider how to select the name of the first document.

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展开它并选择第一个请求，如图19所示。

Expand this and select the first request, as shown in Figure 19.

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If you click on Courseware you will get to this menu, the first of which preferences is Periodic Table.

如果你点击课件，就会来到这个菜单，第一个选择就是周期表。

麻省理工公开课 - 固态化学导论课程节选

The sources are: one,the plasmid vector that we've picked, and the second is these genes that for some reason we're interested in.

第一个是我们选择的质粒载体,第二个是我们感兴趣的基因

耶鲁公开课 - 生物医学工程探索课程节选

Can you go ahead and take 10 more seconds on this first clicker question here? OK.

大家先来花十秒钟的时间,把第一个选择题做了好吗？好。

麻省理工公开课 - 化学原理课程节选