一、现在完成时的构成现在完成时是由“助动词have/has+过去分词”构成的。其中,主语为第一人称单数、第二人称单数或所有人称的复数时,用“have+过去分词”;主语为第三人称单数时,用“has+过去分词”。如:I have taught this class fortwo terms.这个班我已经教了两个学期了。 First, the composition of the present completion is now constituted by the “auxiliary verb have/has+ past participle”. Where the subject is a first-person singular, a second-person singular, or a plural of all, the “have+past participle” is used; when the subject is a third-person singular, “has+past participle” is used. Such as: I have taught this class fortwo terms. This class I have taught for two semesters.