This user has chosen bold formatting for a main heading and bold plus italics for a sub-heading.
该用户为主标题选择了粗体，为子标题选择了粗体加斜体。
2
A heading node may, in turn, contain subheading nodes (level 2) and may also contain some sentences.
一个标题节点，依次，可以包括子标题节点(层次2)，还可以包含有一些句子。
3
Figure 6 lists a few different potential sub-types of problems under the general problem heading of "Application performs poorly or unexpectedly," which Kathy had selected.
图6列出了一些不同的、可能的子类型，这些子类型都隶属于标题为“Application performs poorly or unexpectedly”的问题，即Kathy所选择的类型。