给定一篇英文文章，请将其中的动词变成过去式。
This is a test article to demonstrate verb conjugation. Verb conjugation is the process of changing a verb to indicate the tense and/or the subject of the sentence. It is an important aspect of grammar in many languages, including English.
This was a tested article to demonstrated verb conjugation. Verb conjugation was the processed of changed a verb to indicated the tense and/or the subject of the sentence. It was an importantly aspect of grammar in many languages, including English.