A past participle is the form of a verb that indicates an action took place in the past; it is commonly made by adding "-ed" to the end of the verb. This form can be used in a number of different ways, such as the formation of perfect tenses. The present perfect tense uses it with the auxiliary verb "has" or "have" such as "I have jumped 100 times today," while the past perfect uses the auxiliary "had." A past participle is also typically used with a form of the auxiliary verb "is" to make a sentence in passive voice, such as "The moon was jumped over by the cow."
The most common way in which a past participle of a verb is formed is with the addition of the suffix "-ed" to the simple form of regular verbs. For example, the simple form "jump" can be made into its past participle form by changing it to "jumped" and "guess" becomes "guessed." Irregular verbs, however, are more difficult and do not have a simple form change that occurs. Words like "ring" take on the form "rung," and even more confusion can arise since a similar word like "bring" has the form "brought" rather than "brung."
Perfect tenses are formed through the use of a past participle with one of several different auxiliary verbs. The present perfect is created by adding "has" or "have" to this form of a verb, such as "I have rung the bell today." Past perfect is formed in a similar way, with the use of the auxiliary "had" to form sentences like "I had jumped out of bed every morning until today." These perfect tenses indicate events that have occurred in the past, and can have an impact on the present situation or refer to ongoing past actions.
The past participle is also used to make sentences in passive voice, which should typically be avoided in writing. Active voice in a sentence presents the subject of the sentence first, and describes the action it is taking as well as any objects that are the target of that action. In passive voice, however, the object is presented first and then the action being taken by a subject that is presented later in the sentence.
A line from a popular children's rhyme "The cow jumped over the moon," is in active voice, with the "cow" being the subject of the sentence. When the same past participle of "jumped" is used with the auxiliary "was," it becomes passive as "The moon was jumped over by the cow." This presents the object first, rather than the proper subject and makes the action in the sentence less immediate and interesting.