When the subject of participle is not expressed, it is normally to be the subject of the clause. It is usually poor grammar, and sometimes absurd, if this rule is broken: Trying to be quiet, the floor board creaked. But the rule is often broken when the subject is vaguely understood to be “one”, “we”, “you”, people in general.
The infinitive :
It occurs as a verb in the base form. which may go with or without to, the former being called the to-infinitive (or simple called infinitive as the unmarked form. of the category), and the latter the bare infinitive (as the marked form. of the category).