(used with past participle to form perfect tenses 與過去分詞構(gòu)成完成時態(tài))： She has finished the novel. 她已經(jīng)讀完了那本小說。I had not seen her at least one week by then. 那時我至少有一周沒見到她了。They will～fulfilled the production quota by the end of this month. 到本月底，他們將會完成生產(chǎn)定額。Jennie has been working all day. 珍妮整天在工作。You ought to～noticed it. 你本應(yīng)該注意到這一點的。If I had known (Had I known)， I would～told you. 如果我當(dāng)時知道，我就告訴你了。