时间:2019-01-02 作者:英语课 分类:2017年VOA慢速英语(一)月


英语课

 


Editor's note: See An Introduction to Verb Tenses for the first story in this series.


For VOA Learning English, this is Everyday Grammar.


This is the last in our four-part series on verb tenses. Make sure you see our episodes on progressive and perfect tenses before trying to learn the perfect progressive tenses.


For English learners, the perfect progressive tenses can be scary.


But they are more straightforward than you might think.


When you talk about grammar, perfect means “complete,” and progressive means “unfinished.”


Perfect progressive sentences focus on the completion of an action that is, was or will be in progress.


Think about this sentence in the past perfect progressive:


“I had been waiting for three years by the time my application was approved.” In this example, the emphasis is on duration of the first verb waiting.


Perfect progressive tenses often answer the question how long? There are three perfect progressive tenses: the present perfect progressive, the past perfect progressive, and the future perfect progressive.


Present Perfect Progressive


Let’s start with the present perfect progressive. You form the present perfect progressive by using have been (or has been) followed by an –ing verb.


For instance, “She has been sitting in class since early this morning.” The action, sitting, is continuing. But the emphasis is on the completed part of the action. Here are some more examples:


I have been waiting for 20 minutes.


I have been studying since I was a child.


It has been snowing all day long.


In all of these sentences, the emphasis is on how the finished activity relates to the present.


A time reference is not required to use the present perfect progressive. Sometimes we use it to refer to recently completed actions.


Imagine your friend comes to your house with red, puffy eyes. You might say, “Your eyes are red. Have you been crying?”


Or you notice that a co-worker is looking tanned. You might ask, “You look tanned. Have you have been sunbathing?”


Remember that stative verbs cannot be used in any progressive tense. A stative verb describes unchanging situations, often mental states such as realize, appear and seem.


You should not say, “I’ve been knowing you for a long time.” If you have a stative verb, use the present perfect: “I have known you for a long time.”


Almost all native speakers will contract, or shorten the pronoun that comes before have or has. “I have been” will sound like, “I’ve been.”


Expert grammarian and teacher Betty Azar tells English learners: “Don’t expect slow, careful pronunciation of helping verbs in normal conversation.”


Past Perfect Progressive


Let us move on to the past perfect progressive. The past perfect progressive emphasizes the duration of a past action before another action happened.


For example, “I had been smoking for 10 years before I quit.”


You form the past perfect progressive by using had been followed by an –ing verb.


Notice how the past perfect progressive often includes the adverbs for and since to express duration. You will also see the adverbs before, when or by the time used to introduce a second action.


The second action uses the simple past tense. Here are some more examples:


I had been studying for 12 years by the time I graduated from high school.


She had been living there since she was a child.


He had been teaching for 12 years before he was certified.


The past perfect progressive can also describe a recently completed action. For instance:


My clothes were wet because it had been raining.


He was talking loudly because he had been drinking.


Future Perfect Progressive


We will end with the future perfect progressive. The future perfect progressive describes the duration of an action as it relates to a future event.


There are two ways to form the future perfect progressive. Both require two actions. One is by using “will have been” plus a present participle, followed by “when” or “by the time” and the second action.


For example, “I will have been working for 35 years by the time I retire.” Notice that the second planned action, retire, is in the simple present. The simple future is never used with the second action.


The other way to form the future perfect progressive is using “be going to have been” plus a present participle followed by “when” or “by the time” and the second action. The order of the actions can be reversed with either form.


For example, “By the time the plane arrives, I am going to have been waiting for five hours.”


With the future perfect progressive, it is not always clear if the --–ing verb started in the past or will start in the future. For example, “The doctor will have been working for 24 hours by the time his shift is finished.”


The future perfect progressive is rare because it is difficult to know the duration of an activity relative to another future event.


And those are the three perfect progressive tenses in English.


We have been talking about verb tenses for several weeks now. It is time to move on to other topics. We leave you with a present perfect progressive song by the music band "Foreigner."


"I’ve been waiting for a girl like you


To come into my life"


Words in This Story


straightforward – adj. direct, not complicated


puffy – adj. larger than normal


contract - v. to make (something) smaller or shorter


certified – adj. having met the official requirements that are needed to do a particular type of work


episode - n. part of a longer program, such as a film or television series


tanned - adj. becoming more brown in color


graduated - v. successfully completed a study program


duration - n. the time during which something continues


participle - n. a form of a verb that is used to change a noun or verb 



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age-class distribution
aide dog
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anemogram
anti-anthrax serum
askoli
aura procursiva
axillary sac (or axillary air-sac)
benzoiodhydrin
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carbadipimidine
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cmosfet oscillators
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