动词的过去式,用在一般过去时中,可以作谓语,过去分词是非谓语形式,不可以直接作谓语,需要加助动词。 例如:do~did~done He did his homework just now. His homework was done (by him) just now.(这是被动语态,助动词be+过去分词)。 动词加ing,都是非谓语形式。都不可以直接作谓语。不同的是,一种是现在分词,另一种是动名词。 现在分词,相当于副词,形容词; 动名词,相当于名词。 如果现在分词和助动词be连用,可以构成现在进行时。