present perfect

基本解釋

When you ask about something that started in the past but continues to the present time, you use the Present Perfect tense, e.g.
當(dāng)你談?wù)搹倪^(guò)去開(kāi)始一直持續(xù)到現(xiàn)在的某件事時(shí)，用現(xiàn)在完成法時(shí)態(tài)。
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When you ask about something that started in the past but continues to the present time, you use the Present Perfect tense, e.g.: I’ve been there for 5 years / I’ve been there for 5 years.
當(dāng)你談?wù)撛谶^(guò)去開(kāi)始但是一直持續(xù)到現(xiàn)在的某事時(shí)，用現(xiàn)在完成時(shí)態(tài)，例如：I’ve been there for 5 years/我在那里已經(jīng)5年了。
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If we say when a past event happened (for example, by using time-adverbs), we do not usually use the present perfect.
說(shuō)過(guò)去發(fā)生的事件（例如：用過(guò)去時(shí)間狀語(yǔ)），我們通常不用現(xiàn)在完成時(shí)。
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present t perfect 現(xiàn)在完成時(shí)
Present & Perfect 花圃─批發(fā)
present progressive perfect 現(xiàn)在完成進(jìn)行
present -perfect 是什么意思
Present Perfect Continuous 現(xiàn)在完成進(jìn)行時(shí)態(tài);現(xiàn)在完成進(jìn)行時(shí);行時(shí);第七課

In grammar, the present perfect tenses of a verb are the ones used to talk about things that happened before the time you are speaking or writing but are relevant to the present situation, or things that began in the past and are still happening. The simple present perfect tense uses "have" or "has" and the past participle of the verb, as in "They have decided what to do."