Lifelines are drawn as a box with a dashed line descending from the center of the bottom edge (Figure 3).

生命线画作一个方格，一条虚线从上而下，通过底部边界的中心(图3)。

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Lifelines are drawn as a box with a dashed line descending from the center of the bottom edge (Figure 3).

生命线画作一个方格，一条虚线从上而下，通过底部边界的中心(图3)。

youdao