This is what my friend asked me and he gave out the following examples:
Facebook's new feature translates your post into different languages depending on who's reading it.
Depending on what Duncan decides, Pau Gasol could be the answer for the Spurs.
Kremlin: Russia will ease sanctions on Turkey depending on talks outcome
Now I know that you are supposed to use the present participle form here, any other form just sound strange, but the thing is, I don't know how to explain the word placement, because that phrase is so commonly used, we sort of using it without questioning its property. So is the phrase depending on modify and if it modify a whole sentence, what should we called it and why must it be in the present participle form, grammatically speaking of course.
And correct me if I'm wrong but on the following phrase:
If viewed from the distance, the mountain is beautiful.
The subject of the first clause is also mountain, right?