DANG and Sentence Endings
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This is a binding word, you could think of it translated as and, or a comma. It also binds together two parts, as in chu dang me, water and fire. Note that there are no commas in Tibetan, the ending shad, that long vertical stroke, it not really a dot, or a comma. It just indicates that a specific section ends. A double shad is used to indicate the end of bigger sections, such as a whole chapter.
In many case when translating to English, it's Ok to translate the section up to the dang, and continue with a new sentence with the next section. In the contemporary English culture, short sentences are preferred over very long ones.
So the dang at the end is indicating that the complete sentence is not yet there. There's more to follow. However, we have enough material to translate the first part of the commentary section. We have gone through the words, so next is a matter of rearranging and regrouping it all so it looks good in English.