Verb tense

The Four Principal Parts of a Verb 

Simple

Past

Past Participle

Present Participle (-ing form)

Past Participle

The past participle form of a verb also expresses action that occurred in the past. However, unlike the past tense, the past participle indicates that the action is complete.

You can easily identify the past participle by putting the helping verb had before the verb and then choosing the correct form.

Regular verbs form the past partciple by adding -ed to the simple form, so the past tense and the past participle of a regular verb are the same.

Irregular verbs may form the past participle form by changing the spelling completely—or not at all!

Regular Verbs Simple Past Past Participle slip slipped (had) slipped open opened (had) opened type typed (had) typed

Irregular Verbs Simple Past Past Participle drink drank (had) drunk eat ate (had) eaten drive drove (had) driven

Present Participle (-ing form)
The present participle describes action that is ongoing or continuing. The present participle is formed by adding -ing to the simple form. The present participle does not change regardless of whether the verb is regular or irregular.

	Simple	Past	Past Participle	Present Participle (-ing)
Regular Verbs	open	opened	(had) opened	opening
	type	typed	(had) typed	typing
Irregular Verbs	eat	ate	(had) eaten	eating
	drive	drove	(had) driven	driving

Here's a simple formula to help you identify the principal parts of any verb:

• The simple form of the verb is the infinitive. Identify the simple form by placing the word to in front of the verb and choosing the correct form.
  • to skate
  • to bring
• The past tense of the verb is easily discovered by contextualizing the verb in this sentence:
  

  Yesterday, I _________________.

  • Yesterday, I skated.
  • Yesterday, I brought cookies to class.

• The past participle can be discovered by putting the helping verb had in front of the verb and choosing the correct form.
  • had skated
  • had brought
• The present participle is formed by adding -ing to the simple form of the verb.
  • skating
  • bringing
  
  
  Original Source: http://owlet.letu.edu/grammarlinks/verbs/verb2d3.html