In present participles, you usually add 'ing' to the end. Therefore:

• Talk becomes talking
• Jump becomes jumping
• Open becomes opening
• See becomes seeing

In past participles, you usually add 'ed' to the end. Therefore:

• Talk becomes talked
• Jump becomes jumped
• Open becomes opened

However,

• See becomes seen

Notice how the irregular verb see also did not have a regular past participle. More irregular verbs with irregular past participles are:

• Be, been
• Break, broken
• Eat, eaten
• Slide, slid

As with most irregular words, there is no good 'general rule' which applies, but often 'ed' is replaced by 'en'.

A Participle is a word derived from a verb, participating the properties of a verb, and of an adjective or a noun; and is generally formed by adding ing, d, or ed, to the verb: thus, from the verb rule, are formed three participles, two simple and one compound; as, 1. ruling, 2. ruled, 3. having ruled.

English verbs, not defective, have severally three participles; which have been very variously denominated, perhaps the most accurately thus: the Imperfect, the Perfect, and the Preperfect. Or, as their order is undisputed, they may he conveniently called the First, the Second, and the Third.

The Imperfect participle is that which ends commonly in ing, and implies a continuance of the being, action, or passion: as, being, acting, ruling, loving, defending, terminating.

The Perfect participle is that which ends commonly in ed or en, and implies a completion of the being, action, or passion: as, been, acted, ruled, loved, defended, terminated.

The Preperfect participle is that which takes the sign having, and implies a previous completion of the being, action, or passion: as, having loved, having seen, having written; having been loved, having been writing, having been written.

The First or Imperfect Participle, when simple, is always formed by adding ing to the radical verb; as, look, looking: when compound, it is formed by prefixing being to some other simple participle; as, being reading, being read, being completed.

The Second or Perfect Participle is always simple, and is regularly formed by adding d or ed to the radical verb: those verbs from which it is formed otherwise, are either irregular or redundant.

The Third or Preperfect Participle is always compound, and is formed by prefixing having to the perfect, when the compound is double, and having been to the perfect or the imperfect, when the compound is triple: as, having spoken, having been spoken, having been speaking.

Examples

• He is talking to her.
• They are jumping into the pool.
• We had eaten the pie.

Each of these cases has a verb acting as an adjective, describing the subject.

In case you were wondering, 'had' plus a past participle is called a past perfect.

A part of the text in this article, was taken from the public domain English grammar "The Grammar of English Grammars" (http://www.gutenberg.net/etext/11615) by Goold Brown, 1851.