Present participle (verb-ing) clauses can be used without a subject pronoun and an auxiliary when the subject of the sentence does two things at the same time or when one action interrupts another.

The present participle does not express tense. Nor does it do so to describe the voice when it is used attributively or when ...

Using a participle clause in this way is more characteristic of written English or a literary style, rather than spoken colloquial English. Compare the following: Being French, he is passionate ...