In regular verbs it is the same as the past tense form and is made by adding -ed to the verb stem (or just -d if the verb ends with the letter -e). In Irregular verbs it is formed in different ways.
The past participle is used to form a number of tenses:
Present Perfect: I have smiled.
Past Perfect: I had smiled.
Future Perfect: I shall have smiled.
It is also used to form past tense with Modal Auxiliaries (I might have smiled, I should have smiled, etc.).
For Scientific english editing and Medical Writing Services visitwww.manuscriptedit.com
Tags: "Editing, academic, English, manuscript, medical, proofreading, research paper, scientific, service", writing