When we talk about experience or results, we use the present perfect form.
This form uses "have" followed by the participle.
present perfect form 现在完成形式
participle 英[pɑːˈtɪsɪpl]美[ˈpɑːrtɪsɪpl] n.分词(现在分词或过去分词);
For regular verbs, this participle is identical to the past tense form.
identical 英[aɪˈdentɪkl]美[aɪˈdentɪkl] adj.完全相同的; 相同的; 完全同样的; 同一的;
For irregular verbs, this participle is often different.
When we use the perfect form, the primary focus is on the subject of the sentences, not the verb.
当我们使用完成时句式时，主要关注的是句子的主语，而不是动词。
subject 主语
primary 英[ˈpraɪməri]美[ˈpraɪmeri] adj.初级的; 主要的; 最重要的; 基本的; 最初的; 最早的; 初等教育的; 小学教育的; n.(美国)初选;
It emphasizes condition, experience or results rather than actions or events.
它强调条件、经验或结果，而不是行动或事件。
emphasize 英[ˈemfəsaɪz]美[ˈemfəsaɪz]
v.强调; 重视; 着重; 使突出; 使明显; 重读，强调(词或短语); 加强…的语气;
In these two examples, we see the contrast.
contrast 英[ˈkɒntrɑːst , kənˈtrɑːst] 美[ˈkɑːntræst , kənˈtræst]
n.明显的差异; 对比; 对照; 明显不同的人(或事物); (摄影或绘画中的)颜色反差，明暗对比; （电视屏幕的）图像明暗对比度，反差;
v.对比; 对照; (靠近或作比较时)显出明显的差异，形成对比;
The top sentence gives the condition or state of the subject and the bottom sentence expresses an event.
上面的句子给出了主语的条件或状态，下面的句子表达了一个事件。
state 英[steɪt]美[steɪt] n.状态; 状况; 情况; 国家; 州; 邦; 政府; 正式礼仪，隆重仪式; 美国;adj.国家提供(或控制)的; 国事礼仪(或规格)的; 州的; 邦的;
The top sentence describes the condition of the subject of the sentence, she, rather than an event.
The fact that she has left the hotel is now a part of her experience, or state of being.
he bottom sentence expresses the action, or event: "she left," which is something she did.
In general, the past tense form expresses events or acts, and the perfect form expresses experience or conditions.
When we use the perfect form of the verb we focus on the state of the subject and not an action or event.
（He enjoyed his studies and graduated a few months ago. Now that he has graduated，he's ready to get a job.）
Note that the past form expresses events at specific points or periods of time, such as last year or the past five years
specific 英[spəˈsɪfɪk]美[spəˈsɪfɪk] adj.具体的; 特定的; 特有的; 明确的; 独特的; n.特效药; 特性; 细节; 显著的性质;
These events are distanced from the speaker's point of view.
The perfect form expresses the state of something from the speaker's point of view, not distanced in time.
These two sentences are incorrect and confusing, because they give two different points of view.
Here are some sentences that use the perfect form.
Some are simple, such as the first one, and some are complex, like the last one.
The last one is complex because it combines many verb forms, including the passive.
passive 英[ˈpæsɪv]美[ˈpæsɪv] adj.消极的; 被动的; (动词形式)被动语态的; n.动词被动形式; 被动语态;
