Introduces the doer of an action to show that the subject is being acted upon; if no doer is mentioned, it is placed directly before the verb to indicate the passive voice.

to pick; to pluck; to gather; to select; to mine; to extract

(bound form) to visit; to call on; to look up someone

(bound form) used after a verb, adjective, or noun to represent the person or thing performing an action or possessing a quality; translates as "-er", "-ist", or "one who"