【什么情况下用过去分词】There are two types of passive voice in English that require the use of past participle: 1) passive voice with “be” verb + past participle, and 2) perfect tenses with present perfect and past perfect. Past participle is used to emphasize actions or events that have taken place in the past. There are four main uses of past participle in English: 1) to indicate completion or perfect aspect (e.g. “have done”), 2) to form passive voice (e.g. “be done”), 3) as an adjective or modifier (e.g. “a finished project”), and 4) as a non-finite verb form, including both transitive and intransitive verbs. When used as a predicate with transitive verbs, the past participle indicates passive voice and a passive relationship with the subject of the sentence. When used to express a state or condition, it not only indicates passivity but also emphasizes completion. In the case of intransitive verbs, the past participle used as a predicate indicates an active relationship with the subject and emphasizes the completion of the action. Some past participles used as predicates create sentences that closely resemble passive constructions.
