标志词:just,ever,never,yet,already,for,before,since,so far,recently,twice,still,till now,up to now,three times等。 现在完成时标志词 already 用在肯定句中(be动词、助动词、情态动词之后,实意动词之前)常与yet进行转换。 例如: I have already finished the work. 我已经完成这项工作了。 改为否定句: I haven"t finished the work yet. 我还没有完成这项工作。 改为一般疑问句: Have you finished the work yet? 你完成工作了吗? yet 放在否定句和一般疑问句句末。 其他的标志词:just,before,recently,still,lately,never,ever,twice,on several occasions, in the past / last few days / weeks / months / years,(up to)these few days / weeks / months / years , this week / morning / month / year(多用于一般过去时),up to present,so far,up to now,up till now,till now。 since+时间点=for+时间段=since+时间段+ago since+一般过去时态的时间状语从句。 例如: He has been here since he joined the army. 自从他参军以来,他一直在这儿。 before 表示之前发生的事情,放在句末 例如: I have been to this place before. 我之前去过了这个地方。 just 表示刚刚做过的事情,放在have/has后面 例句: I have just cleaned my room. 我刚刚清理了我的房间。 ever 表示经常的或习惯性的动作,常与表示频率的时间状语连用。放在have/has后面,动词后面 例句: Their debts have grown ever larger. 他们的债务不断增加。 现在完成时 肯定句: He/she/it+has+过去分词 You/We/They+have+过去分词 否定句: He/she/it+hasn"t+过去分词 You/We/They+haven"t+过去分词 疑问句: Have/has+主语+过去分词 点个赞再走吧