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(单词翻译:双击或拖选)
Editor’s note: This is the third episode1 of four-part series on verb tenses. Be sure to listen to part one and part two first.
For VOA Learning2 English, this is Everyday Grammar.
Today we are going to talk about the perfect verb tenses. Perfect tenses generally focus on how a past action affects the present.For example, “I have already eaten.” The suggestion is that the speaker is not hungry.
Perfect verb tenses are the most difficult for English learners. The term “perfect” can be confusing. What does grammar have to do with not making mistakes? When you are talking about grammar, perfect has a different meaning. It comes from the Latin3 word perfectum, which means “complete.”
The most important thing to remember is the perfect tenses always refer to completed actions. If you get confused, try replacing “perfect” with “completed” and the time relationship should become clearer.
We will start with the present perfect. You form the present perfect using has or have followed by a past participle verb. For example, “I have seen Star Wars.”
The use of the present perfect here gives us three pieces of information. First, it tells us that the event is finished. Second, it tells us that the exact time of the action is unknown or unimportant4. Third, it suggests that the experience of seeing Star Wars has some effect in the present.
One of the most difficult distinctions for English learners to make is the difference between the simple past and present perfect.
Remember, when there is a specific time, you use the simple past. In the sentence “I saw Star Wars last night,” the adverb last night is a specific time.
You cannot say “I have seen Star Wars last night.” But, you could say, “I have seen Star Wars before” or “in the past” or “three times.”
You should also use the present perfect to refer to a repeated action in the past. For example, “I have taken that test four times.” The exact time of each action is not important.
You can also use the present perfect to describe an action that did not happen, using the adverb never. “I have never traveled outside of my country” and “I have never smoked in my entire life.” Something that did not happen in the past, like not traveling and not smoking, can also have an effect in the present.
The adverbs never, already, yet and so far are common in the present perfect. Adverbs are often the best indicators5 of which verb tense to use.
Past Perfect
Now let us look at the past perfect. The past perfect describes an activity that was finished before another event in the past. For example, “She had already had a baby before she graduated.”
To form the past perfect, use had followed by a past participle verb. For the second action, use before or by the time followed by the simple past verb. Imagine you were at a New Year’s Eve party, but you fell asleep before midnight. You could say, “I had already fallen asleep before the New Year came.”
You can use the past perfect to talk about how an experience from the distant past relates to an experience from the more recent past. For example, “The soldier wasn’t scared because he had already been in battle before.”
In other words, battle was not a new experience for the soldier.
If the time relationship is clear, you can choose between the past perfect and the simple past. “My grandfather passed away before I was born,” has the same meaning as “My grandfather had passed away before I was born.”
The past perfect just emphasizes7 that the first action was completed before the second action.
Future perfect
Let us move on to the future perfect. Use the future perfect when you know that one future action will be completed before another future action. For example, “I will have graduated from college before my little brother graduates from high school.”
The future perfect has very limited use because we rarely know a future sequence8 of events with any certainty9. When it is used, the future perfect usually refers to major life events that are planned years in advance.
And those are the three perfect tenses. Join us next week on Everyday Grammar for an explanation of the perfect progressive10 tenses.
Words in This Story
participle - grammar. a form of a verb that is used to indicate a past or present action and that can also be used like an adjective11
adverb - grammar. a word that describes a verb, an adjective, another adverb, or a sentence and that is often used to show time, manner, place, or degree
indicator6 - n. a sign that shows the condition or existence of something
scared - adj. afraid of something
1 episode | |
n.(作品的一段)情节,插曲,系列事件中之一 | |
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2 learning | |
n.学问,学识,学习;动词learn的现在分词 | |
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3 Latin | |
adj.拉丁的,拉丁语的,拉丁人的;n.拉丁语 | |
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4 unimportant | |
adj.不重要的,无意义的 | |
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5 indicators | |
(仪器上显示温度、压力、耗油量等的)指针( indicator的名词复数 ); 指示物; (车辆上的)转弯指示灯; 指示信号 | |
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6 indicator | |
n.指标;指示物,指示者;指示器 | |
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7 emphasizes | |
强调( emphasize的第三人称单数 ); 加强语气; 重读; 使突出 | |
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8 sequence | |
n.连续,接续,一连串;次序,顺序 | |
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9 certainty | |
n.必然的事,确定的事实,确信,确实 | |
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10 progressive | |
adj.先进的;前进的,渐进的;进行式的 | |
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11 adjective | |
n.形容词;adj.形容词的,用作形容词的 | |
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