可是在选择元素之前需要理解当前上下文。

Before you can select an element, though, you need to understand the current context.

youdao

就像选择元素和属性一样，也可选择元素中的文本。

Just as you can select elements and attributes, you can select the text within elements.

youdao

从文档中选择元素。

Select elements from a document.

youdao

And this is in contrast to Selection Sort where you're fishing again and again for the then smallest element.

这与选择排序是相反的,在选择排序中你需要一次又一次地,找出最小的元素。

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On the other hand, we've seen n that if the size of a is n, that's to say, we have n elements to choose from, then the number of possible subsets is 2 to the n.

另一方面，我们看到,如果a集合的大小是，也就是说我们有n个元素可供选择，而可能的子集的元素,个数就是2的n次方。

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