Participle Recognition

Definition: A participle is a verb form used as an adjective. The present participle and the past participle of the verb can be used. You learned these two when you studied the principal parts of a verb.

Example:
Verb - walk
Base - (to) walk
Present participle: (is) walking
Past: walked
Past participle: (have) walked

Now the present or past participle can be used as adjectives. Remember that adjectives answer the questions: what kind? how many? which one?. So, the participle will do the same thing.

Example:
The running track is covered with mud.
Running is the participle, describing the noun, track

A participle can come before or after the noun or pronoun it modifies. Remember, too, that the participle is a verb so you need to be careful that it is not part of a verb phrase in the sentence.

Example:
Are you running for president?
Are running is the verb in the sentence

Original Source: http://members.cox.net/lenco1/grammarpractice/participle/participle.htm